DEV Community: Fazle Rabbi

how to get 20 testers for android app

Fazle Rabbi — Thu, 18 Jan 2024 19:40:35 +0000

Google recently made a new policy about publishing Android apps related to 20 people. To publish an app we have to test an Android app with 20 users for 14 days.

But some of the indie developers don’t have a team so they can’t publish their app.

In this situation, we have 70 active people who test the app for 14 days. If you want to test your app and want to publish an Android app on Google Play Console please let me know.

Below you can find my WhatsApp and Telegram numbers. contact with us to help you to publish the app

Whatsapp: wa.me/message/TOEHSXMG5SVAF1
Telegram: https://t.me/fazlerabbiorg

email: fazlerabbi6059@gmail.com

10 ES6 features

Fazle Rabbi — Fri, 28 May 2021 02:42:45 +0000

I will try to introduce the most useful features in a succinct way. After the tutorial, you will possess basic skills and be able to apply them in a real project. Don’t treat it as a guide or documentation. My goal is to encourage you to dig deeper and get familiar with ES6.

const and let keywords const enables you to define constants (finally!). let enables you to define variables. That’s great, but don’t we have variables in JavaScript already? Yes, that’s true, but variables declared by var have function scope and are hoisted to the top. It means that a variable can be used before it has been declared. let variables and constants have block scope (surrounded by {}) and cannot be used before declaration.

2.New cool helper functions appeared, which facilitate work with JS arrays in most useful cases. How many times did you implement logic like: filtering, checking if any or all elements meet the condition, or elements conversion? Probably very often. Now you have great language features to do the work for you

3.We can set the default value with an equal sign when declaring a variable in the parameter of a function.

4.Implementation of very simple functions (like the aforementioned sum or product) requires writing a lot of boilerplate. Is there any remedy for that? Yes, just try arrow functions!

5.classes
Which Java developer doesn’t miss classes when switching to a JS project? Who doesn’t like explicit inheritance, like in Java language, instead of writing magic code for prototypal inheritance? Although some JS developers complained, classes have been introduced in ES6. They don’t change the concept of inheritance. They are just syntactic sugar for prototypal inheritance.

Destructuring
The destructuring syntax is the process of converting elements of an array into variables and converting the properties of an object into variables. In addition, destructuring is a shortcut way to replace one or more elements in a variable from a large object or array.
7.
Enhanced object literals can easily create objects with properties inside the curly braces ({}).
Promises
Promise promises (yes, I know it sounds weird) that you would get in future results of deferred or long-running tasks. Promise has two channels: the first for results, the second for potential errors. To get the result, you provide the callback function as the ‘then’ function parameter. To handle errors, you provide the callback function as the ‘catch’ function parameter.
Please notice that output of the example might differ for each execution, because of random function call.
Arrow Function
The arrow function is a method of shortcut to the function declaration. It will basically shorten our function syntax.
Multiple line String
We can easily write multiple line strings using the backtick symbol.

javascript most common interview questions

Fazle Rabbi — Sat, 08 May 2021 15:45:20 +0000

1. Explain javascript Truthy and Falsy values

In a conditional statement (if, else), usually, we use boolean values true and false. Ture value is known as truthy and false value is known as falsy.

Truthy and falsy value

Truthy

anything that is not mentioned above

falsy

false, '', "", 0, -0, 0n, NaN, null, undefined

Is javascript asynchronous?
Ans: By nature, javascript doesn’t asynchronous, It’s synchronous. But it has lots of features like callbacks, promises, async/await which allows implementation of asynchronous event handling project.

different between “==” and “===”
Ans: == is used for comparing two variables, but it ignores the datatype of the variable whereas === is used for comparing two variables, but this operator also checks datatype and compares two values.

explain this keyword
Ans:The This keyword refers to the current object in a method or constructor.
The most common use of the this keyword is to eliminate the confusion between class attributes and parameters with the same name (because a class attribute is shadowed by a method or constructor parameter).
Explain Scope and Scope Chain in javascript.
Ans: Scope and scope chain are fundamental topics to understand how the javascript engine process and executes code.
To recap:
There are three types of scope: global scope, function scope and block scope
Scopes make possible to have variables with the same name without colliding with each other
Variables and objects in inner scopes are not accessible from outer scopes
Scope chain consists of the variables and objects referenceable by the execution context

What is closure in javascript
A closure is the combination of a function bundled together (enclosed) with references to its surrounding state (the lexical environment). ... In JavaScript, closures are created every time a function is created, at function creation time.

6.What are the differences between null and undefined?
Ans: null is an assigned value. It means nothing. undefined means a variable has been declared but not defined yet.

7.What is event bubble? What are the benefits of event delegate?
Ans: Event bubbling is a type of event propagation where the event first triggers on the innermost target element, and then successively triggers on the ancestors of the target element in the same nesting hierarchy till it reaches the outermost DOM element or document objec

Benefits: Simplifies initialization and saves memory: no need to add many handlers. Less code: when adding or removing elements, no need to add/remove handlers. DOM modifications: we can mass add/remove elements with innerHTML and the like.

8.What are the differences between var, let and const
Ans: var declarations are globally scoped or function scoped while let and const are block scoped. var variables can be updated and re-declared within its scope; let variables can be updated but not re-declared; const variables can neither be updated nor re-declared.

9.What are the differences between normal function and arrow function?
Ans: Regular functions created using function declarations or expressions are constructible and callable. Since regular functions are constructible, they can be called using the new keyword. However, the arrow functions are only callable and not constructible, i.e arrow functions can never be used as constructor functions.

10.What are the usages of map, forEach, filter and find?
Ans: .forEach:
.forEach(), is used to execute the same code on every element in an array but does not change the array and it returns undefined.
.map():
.map() executes the same code on every element in an array and returns a new array with the updated elements.
.filter():
.filter() checks every element in an array to see if it meets a certain criteria and returns a new array with the elements that return truthy for the criteria.

React Developer

Fazle Rabbi — Fri, 07 May 2021 09:11:15 +0000

I here, I am Fazle Rabbi, A specialist on react and I am a full-stack web developer.