DEV Community: Agu O. Wisdom

Learn Vue: Introduction to Vue.js

Agu O. Wisdom — Mon, 14 Aug 2023 14:24:03 +0000

Vue.js is a JavaScript Framework for building Frontend Applications. It is easy to learn, in fact, if you already know HTML, CSS, and JavaScript, then you’re halfway with learning Vue, this is because, Vue.js builds on top of the standard HTML, CSS, and JavaScript, and this makes building frontend applications with Vue easy.

Features of Vue.js

Vue.js is one of the most popular frontend frameworks, let's look at some of the features that make Vue unique.

Declarative rendering: Vue template syntaxes allow us to bind our logic directly to our Template.
Reactivity: With Vue reactivity, we can track the state of our JavaScript, and update the DOM automatically anytime changes are made in our code.
Composable: With Vue.js Composable, we’re able to abstract a piece of code that is shared across our components, thereby reducing code redundancy.
Options API and Composition API: With Vue.js, you have the freedom to choose between the Options API and the Composition API, and use the one that better serves your need.

These are just a few features of Vue, along the way, as you start learning and building with Vue, you will discover more amazing features and why Vue stands out from other frontend frameworks.

Prerequisites

To get the most out of this guide, it's important that you have the following:

Understand the basics of HTML, CSS, and JavaScript.
Node.js is installed on your Machine.
Visual Studio Code or any other text editor is installed on your Machine.

If you’re like me, you wouldn’t want to go through all the stress of installing new software applications before coming back to read the guide. If so, then the Vue Playground is a good alternative. The Vue playground allows us to write and execute any piece of valid Vue.js code. So, if you don’t want to install any software at the moment, then the Vue playground is the way to go.

Setup

I'll be using the Vue.js playground for this guide, but if you prefer using your local dev environment, then run the below command to scaffold a new Vue project with vite:

> npm init vue@latest

The above command installs and executes create vue (the official build tool for Vue). You'll be prompted to answer a series of questions. Use the down or up arrow key to select between yes and no, select no if you're unsure of an option, you can always install them later.

✔ Project name: … <your-project-name>
✔ Add TypeScript? … No / Yes
✔ Add JSX Support? … No / Yes
✔ Add Vue Router for Single Page Application development? … No / Yes
✔ Add Pinia for state management? … No / Yes
✔ Add Vitest for Unit testing? … No / Yes
✔ Add an End-to-End Testing Solution? … No / Cypress / Playwright
✔ Add ESLint for code quality? … No / Yes
✔ Add Prettier for code formatting? … No / Yes

Scaffolding project in ./<your-project-name>...
Done.

cd to the project directory by running the command cd <your-project-name>, run npm install to install all the packages and finally run npm run dev to kickstart the server.

Basic Vue File

Vue.js is used building Single Page Applications (SPAs), SPA means that the app is contained in a single HTML file with different sections.

As a beginner, it’s important to understand the structure of a Vue file. In this section, we’ll go through a basic Vue file and see how it is structured.

A Vue file has a Template section, a Script section, and a Style section with the .vue extension. This is unlike other frontend frameworks, like Angular, where the template is a separate file, and the style and script are also separate files. Vue.js combines the template, script, and style into a single file called component, this makes developing SPA's with Vue simple. You can easily perform any style, template, and script change within a Single-File.

<script setup>
Import { ref } from 'vue'
const myName = ref("Agu Wisdom aka KingstonCodes ")
</script>

<template>
    <h1> {{myName}} </h1>
</template>

<style>
    h1 {
         font-size: 24px;
    }
</style>

The <script></script> contains the logic of the applications, the <template></template> contains the view of the application, and the <style></style>, just as the name suggests, contains the styles of the application.

A Vue.js file on its own is referred to as a component, and we can have as many components as we desire in our Vue application.

Note: _even though we have the freedom to create as many components as we desire in our application, it is also important that we create components only when they are needed.

Data Binding

Data binding is one of the most important features of Vue.js, it is simply the communication between the component's view (Template) and the component's logic (script).

The simplest form of data binding in Vue is string interpolation.

We have three types of data binding in Vue.js; String Interpolation, Directives, and Modifiers.

String Interpolation

String Interpolation is the simplest form of data binding in Vue, it is the way we display texts, strings, or any expression defined in our script. We perform string interpolation in Vue.js by placing the variable or expression we want to interpolate between two curly brackets inside our template. Let’s see this in action:

<script setup>
Import {ref} from 'vue'
const myName = ref("Agu Wisdom")
 </script>

<template>
    <h1> {{myName}} </h1>
</template>

Inside the template, we're using double curly braces {{ ... }} to interpolate the value of the myName variable. This means that the value of myName will be binded to the <h1> element, and any changes to myName will reflect in the browser.

We can also perform any valid JavaScript expression in our template with the help of string interpolation. Below is a basic example:

<template>
  <h1>
     {{ 5 + 5 }}
  </h1>
</template>

Directives

Directives are special attributes in Vue, they are used to manipulate the DOM and control the behavior of our application. Let's see an example of directive with the v-if directive:

<script setup>  
import { ref } from ‘vue’
const isName = ref(true)
</script> 

<template>
<h1 v-if=”isName”> My name is Wisdom </h1>
</template>

The v-if directive is like the traditional JavaScript if statement. In the example above, we are using v-if to tell Vue to only display My name is Wisdom to the browser only when isName is true.

Just as we have the if, else if, and else in JavaScript, we also have v-if, v-else-if, and v-else in Vue. We can use them to control the flow of our Vue application.

Directives are part of the core features of Vue.js, as they help control and shape the flow of our application.
Read more on Vue directives

API Styles

In Vue.js, we have two ways in which we can write our component; we can either use the Options API or the Composition API. I know you are probably wondering, What is Options API? What is Composition API? No worries, we’ll explain and see the differences in a bit.

Options API

The Options API is the old and traditional way of writing Vue.js, mostly used in Vue 2, it allows us to write our component’s logic using a set of options, such as the data, methods, and computed properties.

Here is an example of the Options API:

<script>
export default {
  // Properties returned from data() become reactive state
  // and will be exposed on `this`.
  data() {
    return {
      count: 0
    }
  },

  // Methods are functions that mutate state and trigger updates.
  // They can be bound as event handlers in templates.
  methods: {
    increment() {
      this.count++
    }
  },

  // Lifecycle hooks are called at different stages
  // of a component's lifecycle.
  // This function will be called when the component is mounted.
  mounted() {
    console.log(`The initial count is ${this.count}.`)
  }
}
</script>

<template>
  <button @click="increment">Count is: {{ count }}</button>
</template>

If you noticed, this syntax is different from what we have been seeing in our previous examples, this is because we have been using the Composition API all along.

Composition API

The Composition API was introduced in version 3 of Vue.js (Vue 3), It allows us to write our component’s logic, using a set of imported functions rather than declaring options as we would in the Options API.

With the Composition API, we can write fewer codes as we only import and use the functions we need. Here is the same example above with the Composition API:

<script setup>
import { ref, onMounted } from 'vue'

// reactive state
const count = ref(0)

// functions that mutate state and trigger updates
function increment() {
  count.value++
}

// lifecycle hooks
onMounted(() => {
  console.log(`The initial count is ${count.value}.`)
})
</script>

<template>
  <button @click="increment">Count is: {{ count }}</button>
</template>

This example has fewer codes and different syntax compared to our Options API example; that's because we're only importing the functions we need from Vue.js.

Which API Should I Learn?

This is a question I have heard many beginners ask, but it is important to know that both the Options API and the Composition API serve the same purpose, they are both powered by the same system, and they both work towards achieving the same goal.

My advice to you is; explore both APIs, starting with the Options API as it’s easier to learn and understand, then you can gradually move on to the Composition API later when you have a good understanding of how Vue.js works. But then you can also decide to learn the Composition API first.

Free Resources to Learn Vue

Now that you have a basic understanding of what Vue.js is. It’s time to strengthen your knowledge. Here are 2 free online resources to learn Vue:

Vue official documentation: If you really want to have an Indepth knowledge of Vue, then I think you should give the Vue documentation a try.
Codevolution’s Vue 3 tutorial for beginners: This is probably one of the best introductory courses to Vue.js online. This course covers both the Options API and the Composition API, it starts with beginner's level concepts and builds on it to a much more advanced concepts.

I also recommend that you make your own research and see what you can find, as there are many good resources out there to learn Vue.

Wrapping up

In this introduction to Vue.js for beginners, we have covered some of the key concepts of Vue.js, we have touched on Data Binding, Vue API Styles, and some of Vue's amazing features, and we've also seen some examples. Now that you have an understanding of what Vue.js is and what you can do with it, consider exploring other resources, either free or paid, so you can enjoy the goodness of Vue.js to the fullest.

Learn Vue: List and Conditional Rendering.

Agu O. Wisdom — Sun, 13 Aug 2023 22:34:35 +0000

Imaging you are developing an application, and you want to render some data in the browser based on certain conditions or you have an array of data that you want to loop through and display to in the browser, how can we achieve this Vue? In this guide, we we'll learn List rendering and conditional rendering in Vue and how we can tap into the powers of the v-if and the v-for directives.

List Rendering

The v-for directive is used to render an array of items or an object. The syntax is very simple and easy; item in items where item is the individual item that would be rendered and items is the list we are looping through.

Rendering array with v-for

//template
<div v-for="name in names">{{ name }}</div>

//script

const names = ref(["Vue", "Nuxt", "Vite", "Vitepress"]

v-for will loop through the names array and display each of name in the browser.

Rendering object with v-for

The v-for can also be used to iterate through an object, the sequence of the iterations will rely on the outcome of invoking Object.keys() on the object:

//template
<ul>
  <li v-for="value in myObject">
    {{ value }}
  </li>
</ul>

//script
const myObject = reactive({
  title: 'How to render lists in Vue',
  author: 'KingstonCodes',
  publishedAt: '2023-08-10'
})

Optionally, we can also include the key of each property in the object <li v-for="(value, key) in myObject"> {{ value }} </li>

v-for and key

In order to maintain the state of the items when rendering them to the browser, we can introduce a unique key attribute to reference to each item in the list:

<div v-for="item in items" :key="item.id">
 {{ item }}
</div>

The v-for directive is extremely important as it helps us render lists to the browser effortlessly.

Conditional Rendering

We can render anything to the browser conditionally using either the v-show directive or the v-if directive. Both v-show and v-if can be used to achieve the same result, the difference is that the v-show directive only toggles the CSS display property of the element, hence an element with the v-show directive will always be present in the browser.

v-show

Let's see an example of conditional rendering with the v-show directive.

<div v-show="isTrue">
//content here
</div>

//script
const isTrue = ref(true)

The div will always be rendered in the browser as long as isTrue remains true, likewise, when isTrue is false the div disappears from the browser.

v-if

Like the v-show directive, the v-if directive is also used to conditional render elements to the browser, the element is only rendered when the directive's expression returns a truthy value.

<div v-if="isTrue">
//content here
</div>

//script
const isTrue = ref(true)

Another difference between the v-if directive and the v-show directive is that, we can use v-else and v-else-if directives to match cases where the directives expression isn't true.

v-if with v-else and v-else-if

<div v-if="isTrue < 0">
//display content here
</div>

<div v-else-if="isTrue > 0">
//display content here
</div>

<div v-else>
//display content here
</div>

//script
const isTrue = ref(0)

Like the traditional if, else if, and else in JavaScript, the v-if, v-else and v-else-if can be used to achieve similar result.

In the above example, the v-else block will run because isTrue is neither less than or greater than zero. Similarly, the v-if block or v-else-if block will run depending on whether isTrue is greater than or less than 0

v-for with v-if

Sometimes, we might want to render a list to the browser when certain conditions are met, to achieve this, we need to first loop through the list with v-for then check whether the condition is met with v-if before displaying it.

The problem is, it is not a good practice to use the v-for and v-if directives on the same element, because when they exist on the same element, v-if will have higher level of priority over v-for, meaning that v-if will not be able to access the variable from the v-for block.

<!--
This will not work
-->
<li v-for="todo in todos" v-if="!todo.isComplete">
  {{ todo.name }}
</li>

To fix this, let's move the v-for directive to a wrapper tag.

<template v-for="todo in todos"> 
<li v-if="!todo.isComplete">
  {{ todo.name }}
</li>
</template>

And that's it, the v-for block will always execute before the v-if block, thereby allowing the v-if directive access to the v-for variable and carry out the action.

Learn Vue: Style and Class Bindings

Agu O. Wisdom — Fri, 04 Aug 2023 13:48:43 +0000

Sometimes when working with Vue, we might need to apply some CSS to an element based on some certain conditions. Vue.js provides us with special syntax to dynamically bind our styles and CSS.

Binding to Classes

There are different ways we can bind CSS classes to our html. We can either use the object binding or the array binding

Object binding

We can add CSS dynamically to our html by passing the classes to an object using v-bind:class="{}" syntax. let's see an example of this:

//script
const isBlue = ref(true);

//template
<div v-bind:class="{"blue-text": isBlue}">I'm a blue text</div>

//css
.blue-text {
color: blue;
}

The blue-text class will be added to the div depending on whether the isBlue variable is true or false, in this case it's true, so the blue-text class we be added to the div which will then render:

<div class="blue-text">I'm a blue text</div>

If we change isBlue to false, the class list will updated automatically and accordingly, i.e. the blue-text class will be removed.

We can also add multiple classes to the div like so:

<div v-bind:class="{"blue-text": isBlue, "active": isActive}">I'm a blue text</div>

We can also use the v-bind:class shorthand :class to dynamically bind classes:

<div :class="{"blue-text": isBlue}">I'm a blue text</div>

Array Binding

We can also bind :class to an array like so:

<div :class="[isBlue ? "blue-text" : '']">I'm a blue text</div>

We're using the same example but this time in a different way, we're binding the blue-text class to the div depending on the status of the isBlue variable. When isBlue becomes false the class is removed. Optionally we can add another class to the div to toggle them conditionally:

<div :class="[isBlue ? 'blue-text' : 'red-text']">I'm either a blue or red text</div>

Now when isBlue is false the text changes to red and when isBlue is true the text changes to blue.

Binding to Inline Styles

Just like :class binding, we can also bind styles directly to an HTML element using :style v-bind syntax. Let's see this in action:

Object Binding

<div :style="{color: blue, 'font-size': '20px'}"> I'm a blue text </div>

We can also declare our object directly in the script section to make our code cleaner.

const styleObject = reactive({
  color: 'blue',
  'font-size': '20px'
})

<div :style="styleObject">I'm a blue text</div>

Array Binding

One of the many benefits of binding to an array is that you can bind multiple objects to a single array.

<div :style="[styleObject1, styleObject2, styleObject3]"></div>

Apart from binding object styles to an array, we can also bind our styles directly into the array.

Breaking Into the Tech Ecosystem: Why It's Difficult for Newbies and How to Overcome It.

Agu O. Wisdom — Thu, 06 Apr 2023 23:24:15 +0000

The tech industry is one of the fastest-growing industries in the world, offering lucrative job opportunities and exciting innovation. However, breaking into the tech ecosystem as a newbie can be challenging, even with the increasing demand for tech talent. In this article, we'll explore some of the reasons why it's difficult for newbies to break into the tech ecosystem and provide solutions and advice on how to overcome it.

Reasons Why It's Difficult for Newbies to Break Into the Tech Ecosystem:

Lack of Technical Skills: The tech industry is a highly technical industry that requires specialized knowledge and expertise. Without the necessary technical skills, it can be challenging for newbies to compete with experienced professionals. Additionally, the tech industry is continuously evolving, and new technologies emerge frequently, making it essential to keep up with the latest trends and technologies.
Intimidating Interview Process: Tech interviews are notoriously challenging, and they often involve complex technical questions and coding challenges. Even experienced professionals can struggle with tech interviews, so newbies may find the process overwhelming. Additionally, some companies use screening tools that can be biased against newbies who lack formal experience or education.
Lack of Network: Networking is essential in every industry, and tech is no exception. However, newbies may not have an extensive network of tech professionals, making it difficult to find job opportunities or mentors. Furthermore, some tech jobs are never advertised publicly, so newbies may miss out on these opportunities if they don't have an extensive network.

4.Limited Job Opportunities: The tech industry is highly competitive, and newbies may find it difficult to secure job opportunities. Additionally, many tech companies prioritize experience over education, which can make it challenging for newbies to get their foot in the door. Furthermore, many tech jobs require specific skills and experience, which newbies may not have.

Solutions and Advice on How to Overcome These Challenges:

1.Build Technical Skills: Building technical skills is crucial for breaking into the tech ecosystem. There are many online resources, such as coding bootcamps and online courses, that can help newbies acquire the necessary technical skills. It's essential to focus on building a solid foundation of technical knowledge and continuously learning and adapting to new technologies.

Prepare for Interviews: To prepare for tech interviews, newbies can practice with online resources or work with a mentor who has experience with tech interviews. It's important to research the company and position beforehand, familiarize yourself with the company's products and services, and practice answering technical questions and coding challenges.

3.Network, Network and Network: The importance of networking in the tech industry cannot be over-emphasized. Building a strong network of tech professionals is essential for finding job opportunities and mentorship. Newbies can attend tech events, join online tech communities, or participate in hackathons to meet other tech professionals. It's also essential to leverage social media platforms like LinkedIn to connect with industry professionals.

4.Gain Experience: There are several ways to gain experience in the tech industry, including building a strong portfolio of projects, contributing to open-source projects, and volunteering.

a. Build a Strong Portfolio: Building a portfolio of projects is an excellent way for newbies to demonstrate their technical skills to potential employers. Newbies can create personal projects, work on freelance projects, or participate in hackathons to build their portfolio. It's important to choose projects that showcase a range of skills and technologies and that are relevant to the type of tech job you're interested in.

b. Contribute to Open-Source: Contributing to open-source projects is another way to gain practical experience and build your network. Open-source projects are publicly accessible, collaborative projects that are maintained by a community of developers. Newbies can contribute to these projects by fixing bugs, adding features, or improving documentation. Contributing to open-source projects demonstrates your technical skills and shows potential employers that you are passionate about technology and committed to the community.

c. Volunteer: Volunteering your technical skills can also be a great way to gain experience and build your network. Non-profit organizations, charities, and community groups often need tech volunteers to help with website design, app development, and other technical projects. Volunteering can provide opportunities to work on real-world projects, gain practical experience, and network with other tech professionals.

By building a strong portfolio, contributing to open-source projects, and volunteering, newbies can gain valuable experience, demonstrate their technical skills, and build their network in the tech industry.

In conclusion, breaking into the tech ecosystem as a newbie can be challenging, in fact it's as difficult as learning to code itself, but with dedication, persistence, and hard work, it is possible. Building technical skills, preparing for interviews, networking, and gaining experience are all essential for breaking into the tech industry. By focusing on these areas, newbies can overcome the challenges and succeed in the tech industry.

Creating a RESTful API with JSON Server in Node.js: A Comprehensive Guide.

Agu O. Wisdom — Mon, 27 Mar 2023 22:40:16 +0000

Introduction

JSON Server is a powerful NPM package that allows you to quickly and easily set up a RESTful API with zero coding. It's a lightweight and flexible tool that can be used to simulate a full backend API, making it ideal for prototyping, testing, and developing small to medium-sized applications.

With JSON Server, you can create a fully functional API by just writing a simple JSON file. The server will then use this file to generate a RESTful API, complete with all the necessary endpoints for GET, POST, PUT, DELETE requests, and more. This makes it incredibly easy to get up and running quickly, without having to worry about the complexities of building a backend API from scratch.

In this beginner's guide, I'll show you everything you need to know to get started with JSON Server. I'll walk you through the installation process, show you how to create a JSON file to define your data structure, and demonstrate how to use the API endpoints to retrieve, update, and delete data. Whether you're a seasoned developer or just starting out, this guide will provide you with everything you need to know to get started with JSON Server.

By the end of this guide, you'll have a solid understanding of JSON Server and how it can be used to create a RESTful API with minimal effort. So, let's get started!

Course Structure

This article is divided into the following sections, each covering a key aspect of creating a simple JSON Server file that can be used as a database and supports various API features:

Retrieving all data from the endpoint: Learn how to retrieve a list of items from your JSON Server file and return them as a JSON object.
Querying by ID: Discover how to retrieve a specific item from your JSON Server file by its unique ID.
Filtering: Learn how to filter items in your JSON Server file based on specific criteria.
Sorting: Learn how to sort items in your JSON Server file based on specific fields.
Pagination: Learn how to retrieve a subset of items from your JSON Server file based on page size and page number.
Consclusion: By the end of this article, you will have a solid understanding of how to create a simple JSON Server file that can be used as a database and supports various API features.

Prerequisite

To get the most out of this tutorial, it is necessary that you have the following:

Basic understanding of how a RESTful API works: JSON Server is a tool that allows you to create a RESTful API, so it's essential that you have a basic understanding of how APIs work before diving into this tutorial.
Node.js Installed: JSON Server is built on top of Node.js, so it's essential that you have Node.js installed on your machine before starting. If you don't already have it installed, you can download it from the official Node.js website.

With these two prerequisites in place, you'll be ready to dive into this tutorial and start creating your own RESTful API with JSON Server.

Building a JSON Server API: A Step-by-Step Guide to Setting up, Querying, and Managing Your Data.

This section will guide you through the process of building a JSON Server API. First, let's start by setting up our development environment.

Setting up a JSON Server project.

Installing Json Server: Before we can start building our JSON Server API, we need to install JSON Server. JSON Server can be installed using Node.js and the npm package manager.

To install JSON Server, we need to, first, initialize our project. Open your terminal or command prompt and run the following command:

npm init -y

npm init -y is a command that initializes a new Node.js project with default settings, without prompting the user for any input.

The -y flag tells npm to use default settings for all options, creating a package.json file with default values such as the project name, version, and entry point.

This command is often used at the beginning of a new project to quickly set up a basic project structure and package management for the project. Once that is out of the way, let's now install Json Server. Run the following command in your terminal:

npm install -g json-server

This will install JSON Server globally on your system, making it available for use in any project.

However, if you don't want to install it globally, you can skip the -g flag

Once the installation is complete, you can verify that JSON Server is installed by running the following command in your terminal:

json-server --version

You should see something like this:

bigwiz@bigwiz:~/Documents/jsonwebserver$ json-server --version
0.17.3

Creating a db.json file: The second step in setting up a JSON Server Project is to create a JSON file that will serve as the data source for the server. This file will contain the data that the server will expose through its RESTful API.

The JSON file should be structured as an array of objects, with each object representing a record in the data set. For example, if you were creating a JSON Server to serve data for an ecommerce site, each object in the JSON file might represent a product, with properties like id title, description, price and category.

Once the JSON file is created, it can be used as the data source for the JSON Server.

Now let's create a db.json file with an array of 20 products for our project. Open your text editor and create a file call db.json and insert the following data into it:

{
    "products": [
        {
            "id": 1,
            "title": "product 1",
            "price": 300,
            "category": "cars",
            "description": "Product 1 description"
        },

        {
            "id": 2,
            "title": "product 2",
            "price": 200,
            "category": "accessories",
            "description": "Product 2 description"
        },

        {
            "id": 3,
            "title": "product 3",
            "price": 600,
            "category": "gadgets",
            "description": "Product 3 description"
        },

        {
            "id": 4,
            "title": "product 4",
            "price": 400,
            "category": "accessories",
            "description": "Product 4 description"
        },

        {
            "id": 5,
            "title": "product 5",
            "price": 500,
            "category": "gadgets",
            "description": "Product 5 description"
        },
        {
            "id": 6,
            "title": "product 6",
            "price": 300,
            "category": "accessories",
            "description": "Product 6 description"
        },

        {
            "id": 7,
            "title": "product 7",
            "price": 200,
            "category": "jeweries",
            "description": "Product 7 description"
        },

        {
            "id": 8,
            "title": "product 8",
            "price": 600,
            "category": "gadgets",
            "description": "Product 8 description"
        },

        {
            "id": 9,
            "title": "product 9",
            "price": 600,
            "category": "accessories",
            "description": "Product 9 description"
        },

        {
            "id": 10,
            "title": "product 10",
            "price": 500,
            "category": "gadgets",
            "description": "Product 10 description"
        },
        {
            "id": 11,
            "title": "product 11",
            "price": 300,
            "category": "foods",
            "description": "Product 11 description"
        },

        {
            "id": 12,
            "title": "product 12",
            "price": 200,
            "category": "accessories",
            "description": "Product 12 description"
        },

        {
            "id": 13,
            "title": "product 13",
            "price": 600,
            "category": "cars",
            "description": "Product 13 description"
        },

        {
            "id": 14,
            "title": "product 14",
            "price": 900,
            "category": "accessories",
            "description": "Product 14 description"
        },

        {
            "id": 15,
            "title": "product 15",
            "price": 700,
            "category": "jeweries",
            "description": "Product 15 description"
        },
        {
            "id": 16,
            "title": "product 16",
            "price": 300,
            "category": "clothes",
            "description": "Product 16 description"
        },

        {
            "id": 17,
            "title": "product 17",
            "price": 400,
            "category": "foods",
            "description": "Product 17 description"
        },

        {
            "id": 18,
            "title": "product 18",
            "price": 600,
            "category": "gadgets",
            "description": "Product 18 description"
        },

        {
            "id": 19,
            "title": "product 19",
            "price": 400,
            "category": "accessories",
            "description": "Product 19 description"
        },

        {
            "id": 20,
            "title": "product 20",
            "price": 1000,
            "category": "gadgets",
            "description": "Product 20 description"
        }
    ]
}

After creating the db.json file, the next step is to use it as the data source for the JSON Server.

To use the db.json file as the data source, you need to start the JSON Server by running the following command in your terminal or command prompt:

json-server --watch db.json

This command starts the JSON Server and tells it to watch the db.json file for changes. Any changes you make to the db.json file will be immediately reflected in the API provided by the server.

Once the server is running, you can access the API by navigating to http://localhost:3000/ in your web browser. This will display a list of the available endpoints for your API. You can then use these endpoints to fetch and manipulate the data stored in your db.json file.

Your commandline should display something like this:

 \{^_^}/ hi!

  Loading db.json
  Done

  Resources
  http://localhost:3000/products

  Home
  http://localhost:3000

  Type s + enter at any time to create a snapshot of the database
  Watching...

In the next section, we'll start querying our Json-Server database.

Retrieving all data from the "products" endpoint

Making a GET request is perhaps the simplest, all you have to do is navigate to http://localhost:3000/products and you will get a list of all the products. As you can see, with zero coding we have set up a RESTful API. How sweet is that 😉.

Querying by `ID`

Just like retrieving all the products, We can retrieve a particular product by it's ID, by simply navigating to http://localhost:3000/products/id. Let's assume we want to get the product with the ID of 12 we can simply navigate to http://localhost:3000/products/12 and this will return a single object of the product with id of 12.

Filtering

In this section, we will see how to filter data when making a GET request. Assuming we are building an e-commerce website and the user should have an option to filter a list of product by category. How do we do that with Json Server?. Well that is very simple. All we need to do is navigate to the URL which is http://localhost:3000/products and append a query parameter of the property we want to filter by like so:

localhost:3000/products?category=cars

This will return an array of all the products under the cars category. It's as simple as that.

Sorting

In an e-commerce website, a common requirement is being able to sort the products, lower-to-high or higher-to-low. In our case, let's say we need to sort this products by the price property. How do we do that? again it is very simple. Let me show how to do that. To sort products by the price property, all we need to do is navigate localhost:3000/products and append a query parameter of _sort and set it's value to the property we want to sort by, in this case, it is the price property:

localhost:3000/products?_sort=price

When we make this request, product will be sorted in the ASC order of price. From the lowest all the way to the highest. By deffault, products is sorted in the ASC order, if you want to to sort by DESC order, all you need to do is append &_order=desc to localhost:3000/products?_sort=price like so:

localhost:3000/products?_sort=price&_order=desc

Now th price will go from the highest to the lowest.

Pagination

In this section, let's learn how Json-Sever supports pagination. Right now, If we navigate to localhost:3000/products you will get a list of all the products. But when you are displaying a list of products or if you have a table, pagination is something you might have to support.

To Paginate the data, we append ?_page then we assign a page number. By diffualt, each page returns a list of 10 Items. For example if we specify localhost:3000/products?_page=1 in the URL, by diffualt we will get an array of the first 10 products in our db.json file. Likewise, if we specify the page as 2 we will get the next 10 products and so on.

We can also limit the number of product we want to retrieve like so:

localhost:3000/products?_page=1&_limit=6

This will return an array of the first 6 products in the db.json file. As you can see, it is very easy to serve paginated data with Json Server.

Conclusion

Using JSON server is an easy and efficient way to set up a mock API for your front-end applications. By following the steps outlined in this article, you can quickly create a fake API that closely mimics the behavior of a real one, and test your code without having to worry about the complexities of the backend. So if you're a front-end developer looking for a convenient way to mock an API, you should give JSON server a try.

CONNECTING TO A POSTGRESQL DATABASE WITH NODE.JS: A STEP-BY-STEP GUIDE

Agu O. Wisdom — Mon, 20 Mar 2023 10:08:52 +0000

Introduction

Node.js is a popular open-source JavaScript runtime that allows developers to build powerful and scalable applications.

When it comes to working with databases, PostgreSQL is a top choice for many developers due to its robust features and reliability.
In this guide, I'll show you how to connect your Node.js application to a PostgreSQL database, so you can store and retrieve data with ease. Whether you're building a web app, API, or any other type of application, this guide will give you the knowledge you need to get started.

Prerequisites

Before we get started, there are a few things you'll need:

Basic knowledge of JavaScript and Node.js: This guide assumes that you have some familiarity with JavaScript and Node.js. If you're new to these technologies, I recommend checking out some tutorials to get you up to speed.
Basic knowledge of PostgreSQL: We won't be diving into all the details of PostgreSQL in this guide, it's important that you have a general understanding of what it is and how to use it.
Node.js installed on your machine: To connect to a PostgreSQL database with Node.js, you'll need to have Node.js installed on your system. If you haven't already installed it, you can download the latest version from the official Node.js website.
A code editor: You'll also need a code editor to be able to follow along with this guide. There are many options available, such as Visual Studio Code, Sublime Text, Atom, etc.
PostgreSQL installed on your machine: Finally, you'll need to have PostgreSQL installed on your system. If you haven't installed it yet, you can download the latest version from the official PostgreSQL website.

Once you have all the prerequisites in place, you're ready to learn how to connect to your PostgreSQL database with Node.js.

Connecting to PostgreSQL with Node.js

To connect to a PostgreSQL database with Node.js, We'll need to follow these steps:

Installing Dependencies

We'll be needing the following packages for this guide:

pg: This is the official PostgreSQL client for Node.js. It provides a simple API for querying the database and handling the results. We'll use it to establish a connection to our PostgreSQL database.
db-migrate-pg: This is a PostgreSQL driver for the db-migrate library. It provides an easy way to manage database migrations, which are changes to the database schema over time. We'll use it to create and update our database schema as needed.
dotenv: This is a zero-dependency module that loads environment variables from a .env file into process.env. We'll use it to store our database connection details securely.

To install these dependencies, open your terminal, navigate to your project directory and run the following command:

npm install pg db-migrate-pg dotenv

This will install the latest versions of each package and add them to your project's node_modules directory.

Creating a Database Connection

Before we can connect to our PostgreSQL database, we need to create a new database in the psql terminal. Open your terminal and enter the following command:

CREATE DATABASE your_database_name

Replace your_database_name with a name for your database. This will create a new database with the specified name.

Now that we have a database set up, let's create the necessary files to connect to it. We'll need to create the following files:

server.js This is where we'll write some code to establish a connection with PostgreSQL using the pg package.
.env file: This is where we'll store our environment variables, including our database connection details. It's important to use an .env file in our project to keep sensitive information like database passwords and connection details secure.
database.json file: This is where we'll store the information for testing that our database was successfully connected.

Let's start by creating the server.js file. In this file, we'll establish a connection with our PostgreSQL database using the pg package.

Open the server.js file and add the following code:

require ('dotenv').config();
const { Pool }  = require ('pg');


const {
POSTGRES_HOST,
POSTGRES_DB,
POSTGRES_USER,
POSTGRES_PASSWORD
} = process.env

export const Client = new Pool({
    host: POSTGRES_HOST,
    database: POSTGRES_DB,
    user: POSTGRES_USER,
    password: POSTGRES_PASSWORD
});

In this code, we're using the pg package to create a new pool instance using the database connection details loaded from our .env file. We then export this pool instance so that it can be used elsewhere in our application.
A typical use case is when we are creating models for our database, we can import it into our model file and use it to establish a connection with our database.

Next, let's create the .env file. This file should be located in the root directory of your project, and it should contain the following lines:

POSTGRES_USER=your_database_username
POSTGRES_HOST=your_database_host
POSTGRES_DB=your_database_name
POSTGRES_PASSWORD=your_database_password

Replace each of the your_database_* values with the appropriate values for your database connection. Please make sure that this file secure, as it contains sensitive information.

Finally, let's create the database.json file. This file should be located in the root directory of your project, and it should contain the following lines:

{
  "dev": {
    "driver": "pg",
    "user": "your_database_username",
    "host": "your_database_host",
    "database": "your_database_name",
    "password": "your_database_password"
  }
}

Replace each of the your_database_* values with the appropriate values for your database connection. This file is used for running our database migration to ensure that our database connection is working. This file should also be kept secure.

Running Database Migration.

Finally, to test that we have successfully connected to our database, let's create a database migration using db-migrate-pg

Step 1. Run the following command to create a database migration:

db-migrate create users --sql-file

This command is telling db-migrate-pg to create a migration of users.

If the command ran successfully, you should see a folder named migration in the root folder of your project. Your root folder should look like this:

├── database.json
├── migrations
│   ├── 20230318081649-users.js
│   └── sqls
│       ├── 20230318081649-users-down.sql
│       └── 20230318081649-users-up.sql
├── package.json
├── package-lock.json
└── sever.js

Step 2. Create a Table

Inside the sqls sub-folder of the migration folder, open the users-up-sql file and insert the following code:

CREATE TABLE users(
    name VARCHAR(100),
    email VARCHAR(100),
    password VARCHAR
);

Open the users-down-sql file and insert the following code:

DROP TABLE users;

The above codes will create and drop the users table respectively in the database.

Step 3. Run the Migration

Finally, let's run the migration using the following command:

To Create the users table, run:

db-migrate up

This command will run the code in the users-up-sql file and create the table users in the database.

If the code ran successfully, then your terminal output will look like so:

bigwiz@bigwiz:~postgres/pg-node_tut$ db-migrate up
received data: CREATE TABLE users(
    name VARCHAR(100),
    email VARCHAR(100),
    password VARCHAR
);
[INFO] Processed migration 20230318081649-users
[INFO] Done

Now check your database to ensure that everything was successful, your database should look like so:

       List of relations
 Schema |    Name    | Type  | Owner 
--------+------------+-------+-------
 public | migrations | table | me
 public | users      | table | me
(2 rows)

To DELETE the table, run the following command:

db-migrate DOWN

The above command will run the down migration in the users-down-sql file.

That's it! With everything in place, we can now establish a connection to our PostgreSQL database using Node.js.

Conclusion

Connecting to a PostgreSQL database with Node.js is an essential skill for any backend developer. By following the steps outlined in this article, you should now have a good understanding of how to establish a connection with PostgreSQL.

Additionally, you now understand how to also create database migrations in PostgreSQL. Remember to always keep your code organized and secured.

Analyzing and visualizing trace data to identify performance bottlenecks and optimize system performance.

Agu O. Wisdom — Wed, 15 Mar 2023 12:59:01 +0000

As the complexity of modern web applications continues to increase, so does the importance of monitoring and optimizing performance. Distributed tracing is a powerful technique for monitoring the flow of requests and responses across multiple services, but the real value of distributed tracing lies in its ability to identify performance bottlenecks and optimize system performance.

In this article, we will explore how to analyze and visualize trace data to identify performance bottlenecks and optimize system performance. We will cover the following topics:

Introduction to Distributed Tracing
Analyzing Trace Data
Visualizing Trace Data
Using Trace Data to Identify Performance Bottlenecks
Optimizing System Performance
Conclusion

Introduction to Distributed Tracing

Distributed tracing is a technique used to monitor and debug distributed systems, where multiple services are involved in handling a single request. It involves generating and propagating a unique identifier across various components of the system to track the flow of requests and responses.

In a Node.js application, distributed tracing can be implemented using open-source tools like Jaeger, Zipkin, or AWS X-Ray. These tools allow developers to instrument their code by adding tracing headers to HTTP requests, logging events to a centralized tracing system, and visualizing the trace data in real-time.

Analyzing Trace Data

Once trace data has been collected, it can be analyzed to gain insights into system performance. The trace data typically includes information about the duration of each operation, the components involved, and any errors or exceptions that occurred.

There are several techniques that can be used to analyze trace data, including statistical analysis, machine learning, and anomaly detection. Statistical analysis can be used to identify trends and patterns in the data, while machine learning can be used to detect anomalies and predict potential issues before they occur.

For example, let's say we have a Node.js application that handles a high volume of user requests. We can use distributed tracing to collect and analyze trace data to identify any bottlenecks or areas of the system that are causing delays. By analyzing the trace data, we may discover that a particular service or function is taking longer than expected to complete its task, causing delays in the overall response time.

Visualizing Trace Data

Visualizing trace data is an important aspect of analyzing it, as it allows developers to quickly identify patterns and trends. There are several visualization techniques that can be used to visualize trace data, including flame graphs, heat maps, and histograms.

For example, let's say we have a Node.js application that involves multiple services communicating with each other to fulfill a user request. We can use a flame graph to visualize the duration of each operation and identify any functions or services that are taking the most time to complete. We can then use this information to optimize those functions or services to improve system performance.

Using Trace Data to Identify Performance Bottlenecks

The real value of distributed tracing lies in its ability to identify performance bottlenecks and optimize system performance. By analyzing and visualizing trace data, we can identify areas of the system that are causing delays and take steps to optimize those areas.

For example, let's say we have a Node.js application that involves multiple services communicating with each other to fulfill a user request. By analyzing the trace data, we may discover that a particular service or function is causing delays in the overall response time. We can then optimize that service or function by improving its performance, caching data, or optimizing its algorithms.

Optimizing System Performance

Once we have identified performance bottlenecks and areas for optimization, we can take steps to improve system performance. This may involve optimizing code, tuning database queries, or using caching to reduce response times.

For example, let's say we have a Node.js application that involves multiple services communicating with each other to fulfill a user request. By analyzing and visualizing the trace data, we may discover that a particular database query is causing delays in the overall response time. We can then optimize that query by adding an index or optimizing its structure to improve its performance.

Conclusion

In conclusion, distributed tracing is a powerful technique for monitoring and optimizing the performance of modern web applications. By collecting and analyzing trace data, developers can identify performance bottlenecks and take steps to optimize system performance. Visualizing trace data is an important aspect of analyzing it, as it allows developers to quickly identify patterns and trends. With the right tools and techniques, developers can use distributed tracing to improve the performance and scalability of their Node.js applications.

TypeScript and Node.js: Building Scalable and Robust Applications.

Agu O. Wisdom — Wed, 15 Mar 2023 09:26:32 +0000

Node.js is a popular JavaScript runtime that allows developers to build efficient and scalable web applications. It enables developers to write server-side applications using JavaScript, which makes it easy to use the same language on both the frontend and backend.

However, as applications grow in complexity, it becomes difficult to maintain them. This is where TypeScript comes in - a superset of JavaScript that adds static type checking and other advanced features to the language.

In this article, we will explore how TypeScript and Node.js can be used together to build scalable and robust applications.

Examples

To demonstrate how TypeScript and Node.js can be used together, we will write a simple application that reads a file and logs the result in the console. We will first write the code in JavaScript and then convert it to TypeScript.

JavaScript Code

const fs = require('fs');

fs.readFile('example.txt', 'utf8', (err, data) => {
  if (err) throw err;
  console.log(data);
});

This code uses Node.js' FS module to read a file named example.txt and log its contents to the console. The fs.readFile() method reads the file asynchronously and takes a callback function that is called when the file is read. If there is an error while reading the file, the err parameter will contain the error information.

TypeScript Code.

Now, let's convert the above JavaScript code to TypeScript. We will start by installing the TypeScript compiler. In your terminal run:

npm install -g typescript

And finally, run npx tsc --init this will add the typescript config file to your project.

We can then create a TypeScript file named app.ts and write the following code:

import fs from 'fs';

fs.readFile('example.txt', 'utf8', function(err: NodeJS.ErrnoException | null, data: string) {
  if (err) throw err;
  console.log(data);
});

Here, we are using TypeScript's import statement to import the fs module. We have also specified the types of the err and data parameters. The err parameter can either be null or an instance of NodeJS.ErrnoException. The data parameter is a string type.

TypeScript provides static type checking, which means that it can catch errors at compile time, before the code is run. In the above code, if we try to assign a value of the wrong type to a variable or parameter, TypeScript will throw a compile-time error. This can save developers a lot of time and effort in debugging and testing their code.

Why TypeScript is Better with Node.js

TypeScript offers several advantages over JavaScript when it comes to building Node.js applications. Here are some of the reasons why TypeScript is better with Node.js:

Static Type Checking: TypeScript provides static type checking, which ensures that variables and parameters have the correct type. This leads to more stable and reliable code, which is easier to maintain.
Advanced Features: TypeScript adds several advanced features to JavaScript, including interfaces, classes, and enums. These features allow developers to write more expressive and maintainable code.
IDE Support: TypeScript has excellent support for IDEs, including code completion, code highlighting, and error highlighting. This makes it easier for developers to write code and catch errors.
Better Code Readability: TypeScript code is often more readable than JavaScript code, especially when it comes to complex applications. This is because TypeScript provides additional information about the code, including type information and function signatures.

In conclusion, TypeScript and Node.js provide developers with a powerful tool set to build efficient, scalable, and maintainable web applications. By using TypeScript with Node.js, developers can catch errors early in the development process, improve code quality, and increase productivity. With the benefits that TypeScript brings to the table, it's no surprise that more and more developers are adopting it for their Node.js projects.

PostgreSQL SELECT STATEMENT.

Agu O. Wisdom — Tue, 14 Mar 2023 22:43:13 +0000

How to use the PostgreSQL `SELECT` statement.

In this short tutorial, you are going to learn how to use the Postgres SELECT statement to query the database and retrieve information from a table.

The Postgres SELECT statement is one of the most used queries in SQL, it is used to retrieve data from tables. It is part of the queries used to perform CRUD (Create, Read, Update, Delete) operations in SQL. The SELECT statement is the READ in the CRUD operations, since it is used to read or retrieve data.

Let's see an example of how to use SELECT.
The following shows an example on how to use SELECT:

SELECT list_name FROM table_name;

Now, let's break it down:

First, specify a list, can be a column or list of columns from the table you want to query.
Ensure that the data you want to retrieve exists in the table.
If you are selecting multiple columns, you need to use comma , after each column name.
Use the asterisk * shorthand to retrieve all the columns from a table (not a good practice).
The FROM clause specifies the table you want to select from.
And finally, the table name, which is the name of the table you want to select from.

NOTE: In PostgreSQL, the semicolon at the end of the table name is not optional. If you skip the semicolon, Postgres will throw an error.

Conclusion: In this short tutorial, you have learned how to use the PostgreSQL SELECT to query a database and retrieve information from a table.

DEV Community: Agu O. Wisdom

Learn Vue: Introduction to Vue.js

Features of Vue.js

Prerequisites

Setup

Basic Vue File

Data Binding

String Interpolation

Directives

API Styles

Options API

Composition API

Which API Should I Learn?

Free Resources to Learn Vue

Wrapping up

Learn Vue: List and Conditional Rendering.

List Rendering

Rendering array with v-for

Rendering object with v-for

v-for and key

Conditional Rendering

v-show

v-if

v-if with v-else and v-else-if

v-for with v-if

Learn Vue: Style and Class Bindings

Binding to Classes

Object binding

Array Binding

Binding to Inline Styles

Object Binding

Array Binding

Breaking Into the Tech Ecosystem: Why It's Difficult for Newbies and How to Overcome It.

Reasons Why It's Difficult for Newbies to Break Into the Tech Ecosystem:

Solutions and Advice on How to Overcome These Challenges:

Creating a RESTful API with JSON Server in Node.js: A Comprehensive Guide.

Introduction

Course Structure

Prerequisite

Building a JSON Server API: A Step-by-Step Guide to Setting up, Querying, and Managing Your Data.

Setting up a JSON Server project.

Retrieving all data from the "products" endpoint

Querying by ID

Filtering

Sorting

Pagination

Conclusion

CONNECTING TO A POSTGRESQL DATABASE WITH NODE.JS: A STEP-BY-STEP GUIDE

Introduction

Prerequisites

Connecting to PostgreSQL with Node.js

Conclusion

Analyzing and visualizing trace data to identify performance bottlenecks and optimize system performance.

TypeScript and Node.js: Building Scalable and Robust Applications.

Examples

Why TypeScript is Better with Node.js

PostgreSQL SELECT STATEMENT.

How to use the PostgreSQL SELECT statement.

Querying by `ID`

How to use the PostgreSQL `SELECT` statement.