Require Js Interview Questions & Answers
Require Js Interview Questions
Require Js Jobs
All Interview Questions-
Question 1. What Is The Role Of Optimizer?
Answer :
The Optimizer is a built process where your project is deployed to end user and its combines all scripts/css files together and minify them.
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Question 2. How To Use Require Js With Jquery?
Answer :
The Require JS uses jQuery and lots of another dependency i.e.
require(['jquery'], function ($) {
//jQuery was loaded and can be used now.
});
-
Question 3. What Is Amd Module?
Answer :
The AMD is stands for Asynchronous Module Definition and is used for defining modules and their dependencies with asynchronous manner.
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Question 4. What Is Data-main Attribute?
Answer :
The data-main attribute is an attribute that Require JS will check to start script loading. The data-main set to the base URL for all the scripts.
Example:-
<!DOCTYPE html>
<html>
<head>
<script data-main="libs/main" src="libs/require.js"></script>
</head>
<body>
<h1> RequireJS Sample apps</h1>
</body>
</html>
-
Question 5. What Is Module In Require Js?
Answer :
Module is independent unit of program which make easy maintenance and reusability of code. In RequireJs we talk about JavaScript module.
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Question 6. What Is The Project Structure Of Require Js?
Answer :
Project directory and the structure looks like:-
- app.js
- index.html
- lib
- modules
- template.js
- require.js
- jquery.js
- underscore.js
-
Question 7. What Is Config Function?
Answer :
The Require JS can be initialized by passing the main configuration in the HTML template through the data-main attribute.
If you want to update the Require JS configuration values with your own configurations value. You can do using the require js. Config function.
The configurations options:-
- config - This is for configuration to a module by using the config option
- baseUrl -This is the root path to start the loading of modules.
- paths - this is the path mapping for modules that don’t exists in under the base URL.
- Shims - This is use for configuration for dependencies.
- deps - array of dependencies to load
- url Args -This is the query string arguments are used to fetch all resources that are loaded by using Require JS.
- callback -It executes a function after loading the dependencies and is required when Require is specified as config object before loading Require JS.
- xhtml - It is used to create the script elements by using the document.createElement() method.
- script Type - It defines the value for script type attribute used in the document. Default type is "text/javascript".
Example looks like:-
require.config({
baseUrl: 'scripts/app',
paths: {
lib: '../lib'
},
shim: {
'backbone': {
deps: ['underscore'],
exports: 'Backbone'
}
}
});
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Question 8. What Are Asynchronous Module Definition (amd) Modules?
Answer :
Defining Modules:-The Module is defined using define () method and it used for loading the module i.e.
define({
country:"India",
state: "UP",
city: "Noida",
userDetail: function () {
return "User Detail";
}
});
Defining Functions:- A module can also use a function without dependencies i.e.
define(function () {
return {
country:"India",
state: "UP",
city: "Noida"
}
});
Defining Functions with Dependencies:- The Dependencies module looks like.
define(["../comp", "../user"],
function(comp, user) {
return {
country:"India",
state: "UP",
city: "Noida",
addUser: function() {
comp.decrement(this);
user.add(this);
}
}
});
Defining a Module as a Function:- Its looks like.
define(["../comp", "../user"],
function(comp, user) {
return function(userName){
return userName != null ? userName :'NA'
}
});
Defining a Module with a Name:- Its looks like.
define("Users", ["../comp", "../user"],
function(comp, user) {
return {
country:"India",
state: "UP",
city: "Noida",
addUser: function() {
console.log(this);
}
}
});
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Question 9. When Should I Use Require () And When To Use Define ()?
Answer :
The define () method looks like:-
- The define () method is used for facilitating module definition
- The define () method accepts two optional parameters module ID and array of required modules [dependencies]
- The define () method MUST return the implementation for your module i.e.
define(
module_id /*optional*/,
[dependencies] /*optional*/,
definition function /*function for instantiating the module or object*/
);
And
define (['moduleA', 'moduleB'], function (moduleA, moduleB) {
//define the module value by returning a value
return function () {};
});
The require () method looks like:-
- The require () method is used for handling dependency loading
- The require () function doesn't have to return the implementation of a new module.
require(['jquery'], function ($) {
//jQuery was loaded and can be used now.
});
Example 1:-
define( 'MyApp', ["marionette"], function (Marionette) {
// set up the app instance
var app = new Marionette.Application();
app.on("initialize:after", function(){
console.log("initialize started.");
});
// export the app from this module
return app;
});
Example 2:-
// Fetch and execute Marionette App
require( ["MyApp"], function (app) {
// Execute App
app.start();
});
Example 3:-
define({
"root": {
"india": "india",
"australia": "australia",
"england": "england"
}
});
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Question 10. What Are Disadvantage Of Require Js?
Answer :
- No support for AMD in Node.js
- Not all modules implement AMD
-
Question 11. What Are The Main Features Of Require Js?
Answer :
- Require JS manages the dependencies between JavaScript files and improves the quality of the code and application speed.
- It is combines and minifies the modules into one script for speed-up.
- Require JS Collecting the different JavaScript files from different modules at the compilation time.
- Easy debugging
- Lesser HTTP requests
- Reduce code Complexity in large application.
- And so on.
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Question 12. How To Define Entry Point For Require Js?
Answer :
We need to define an html file and it could be "index.html" where Require JS is loading i.e.
<!DOCTYPE html>
<html>
<head>
<script data-main="libs/main" src="libs/require.js"></script>
</head>
<body>
<h1> Require JS Sample apps</h1>
</body>
</html>
In above example, the data-main attribute of require.js will start initialization of files.
-
Question 13. Why Do People Use Require Js? What Are The Benefits?
Answer :
- It is an open source JavaScript library.
- It is AMD compatible asynchronous module loader.
- It is Asynchronous by nature.
- Lazy loaded on-demand.
- It is easily portable.
- It is Avoids global variables.
- It has ability to load nested dependencies.
- Its Dependencies are easy to identify.
- It can be easily configured.
- It can load multiple versions of the same library.
- It will make the website more optimize and speed.
-
Question 14. How To Install Require Js?
Answer :
You can install the latest release of Require JS from the command prompt using the below commands-
//Install the Require JS package
npm install -g require js
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Question 15. What Is Require Js?
Answer :
- Require JS is a JavaScript library and AMD compatible asynchronous module loader.
- Require JS is used to loads the JavaScript files and resolve their dependencies and its supported to the latest versions of popular browsers.
- Require JS helps to improve the performance and code of quality.
- Require JS was developed by David Mark. Its open source and it was released in 2009.
- Require JS is used by node.js to fetch and load module.
- Require JS contains a small set of plugins which allow us to loading the various types of resources like text, Dom Ready, i18n, CSS and loading.
Require JS includes three main API functions:-
- Define () - This function is used to define a module. Each module is defined a unique module ID. This module Id is used by Require JS at the runtime.
- Require () - This function is used to load dependencies and It is a global function.
- Config () - This function is used to configure the Require JS runtime functionality.
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