DEV Community: Khalil Dev

Type Conversion In JavaScript

Khalil Dev — Fri, 17 Feb 2023 08:04:29 +0000

To change the type of a value in JavaScript, it is necessary to perform type conversion, which implies transforming the data type from its original state to a distinct one.

There are two main ways to perform type conversion in JavaScript:

1. Implicit Type Conversion (Type Coercion):
JavaScript automatically performs type conversion in certain situations, such as when using operators or functions with operands of different types.

Implicit conversion to String:

Implicit conversion to Number:

2. Explicit Type Conversion:
You can also perform type conversion explicitly using functions such as parseInt(), parseFloat(), String(), Number(), Boolean(), and toString().

Explicit conversion to Number

Explicit conversion to String

Explicit conversion to Boolean

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JavaScript Data Types

Khalil Dev — Thu, 16 Feb 2023 03:39:37 +0000

In JavaScript, there are different types of data that can be used to represent different kinds of information. These data types can be broadly categorized into two categories: primitive and object.

Primitive Data Types
In JavaScript, a primitive datatype is a data type that represents a single, immutable value.

There are six primitive datatypes in JavaScript:

1. string
It represents textual data, enclosed with single or double quotes.

2. Number
Number represents numeric data, including integers, decimals. It also represent special values like Infinity and NaN(Not a Number).

3. Boolean
It represents a logical value, which can be either true or false.

4. Null
It represents a special value that signifies the absence of any object value.

5. Undefined
It represents a special value that signifies the absence of a value.

6. Symbol
Symbol represents a unique and immutable data type, which is often used to define object properties that should not be altered.

Primitive Data Types can be declared like below:

Object Data Types
An object is a composite data type that represents a collection of related data or functionality. Unlike primitive data types that represent a single value, objects can hold multiple properties and methods, and are used to represent more complex data structures.

There are three types of object.
1. Object
Object represents a collection of related data or functionality, typically defined using object literals, object constructors, or classes.

2. Array
Array represents a collection of ordered data, typically defined using array literals or the Array constructor.

3. Function
It represents a block of code that can be called or invoked, typically defined using function declarations or function expressions.

4. Date
Date represents a specific point in time, typically defined using the Date constructor or Date.parse method.

Summary
There are two main Data Types in JavaScript. Primitives are Number, String, Boolean, Null, Undefined, Symbol. Non-Primitives are Object, Array, Function and Date.

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JavaScript Variable

Khalil Dev — Tue, 14 Feb 2023 03:32:45 +0000

What is variable in programming language?
A variable is a named storage location that holds a value. Variables are used to store data values that can be used later in your code. The value of a variable can be changed, as well as its data type, throughout the execution of a program.

How to create variable in JavaScript?
To declare a variable in JavaScript, you use the var, let, or const keywords, followed by the variable name. Let's declare a few variable.

Variable declared using var
The var keyword is used to declare a variable with function scope, which means that the variable is accessible within the entire function where it was declared.

Variable declared using let
The let keyword is used to declare a variable with block scope, which means that the variable is accessible only within the block in which it was declared.

Variable declared using const
The const keyword is used to declare a constant, which is a variable whose value cannot be changed.

How to name a variable?
It's good practice to use descriptive names for your variables to make your code more readable and easier to maintain. Avoid using reserved words as variable names, and use camelCase or snake_case to separate words in your variable names

Summary
Variable is used to store data. In JavaScript, a variable is declared using var, let and const. It's best practice to give descriptive name to variable.

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JavaScript Fundamental Briefing

Khalil Dev — Thu, 09 Feb 2023 11:48:48 +0000

Hey programmers!

I hope you have a productive day. This post briefly covers the fundamental of JavaScript programming language. Since fundamental is the most crucial step, it is useful to refresh it after sometimes again and again. It is also important for newbies where to start and move to next one.

Okay! Let's dive in with a bit of motivation.

1. Why JavaScript?
JavaScript has a huge eco system now. It can be used in frontend or UI development, backed or server-side development, desktop application development and even in machine learning. To master it, it is crucial to understand the fundamentals first. Here is a simple roadmap:

2. Variables declaration
Like other programming languages, JavaScript also declare and use variables but a little bit differently. Keywords let, var and const is used to declare variables. const is used to declare constants in JavaScript. Read more

3. Data types
Data type helps program to operate correctly on data. In JavaScript, there are two main types of data; primitive and non-primitive. Primitive data type includes String, Number, Bigint, Boolean, Symbol, Null and Undefined. While non-primitive includes objects and arrays.Read more

4. Type conversion
Sometimes data needs to be converted from one type to another one. For example; converting a string to a number or number to Boolean and vice-versa. JavaScript provides methods to do type conversion. Read more

5. Math Operation
There are several math operations namely “unary”, “binary”, “operant”, basic mathematic operation, reminder operator, exponentiation, string concatenation, assignment operator, increment and decrement operator, bitwise operators. Each of these operations have important role when manipulating data.

6. Variable comparison

Comparing two values is normal in every programming language. In JavaScript, it can be done by greater than, less than, equal, not equal, type comparison and string comparison operators.

7. If and switch statement
Sometimes, it is needed to perform different actions based on different conditions. There are three popular ways to do this. One way is using if statement, another is if ... else statement and last one is switch statement. Each of the statement is used to check conditions but they should be used in its suitable places.

8. Logical Operators
Logical operators provide another way to check conditions. In JavaScript, there are four logical operators which are OR (||), AND (&&), NOT (!), and Nullish Coalescing ( ?? ).

9. Loops
Loop is a block or a piece of code which is used to execute a repeated task. Basically, there are three types of loops such as for, while, and do...while loops. Beside these, JavaScript provides a few more way to loop over a list of data such as forEach, for...of and for...in loops.

10. Functions
Function is a block of code which is used to execute a particular task. It can be called in different place as much as needed. It’s important to understand function declaration, function parameter, default and alternative parameter, arguments, and return value.

In addition to the above, In JavaScript there also feature like function expression, arrow function and callback functions that need to be understood.

11. Objects
In JavaScript, an object is a collection of key-value pairs, where the keys are strings or symbols and the values can be any type of data, including primitive values (e.g., numbers, strings, and Booleans) or other objects.

12. HTM DOM
The Document Object Model (DOM) is a programming interface for HTML and XML documents. It represents the structure of a document as a tree of nodes, where each node corresponds to an element or an attribute in the document.

13. Other JavaScript specials
Interaction
Natively, JavaScript printout a variable either in console or on-screen pop-up. Console log is the most popular way to console things while coding because it prints out data in several beautiful ways.

Strict mode
Putting “use strict” at the top of JavaScript file enable all features of modern JavaScript. This should be written at the top (first line).

Without "use strict", everything still works, but some features behave in the old-fashioned, “compatible” way. We’d generally prefer the modern behavior.

What's next
I will write more and inadept explanation with code examples about each of the above topics. If you are looking for premium content about web development stick around.

I will also write about CSS and web development frameworks like ReactJS and NodeJS.