Javascript Libraries

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Definition:

A JavaScript library is a library of pre-written JavaScript which allows for easier development of JavaScript-based applications, especially for AJAX and other web-centric technologies.
One must not confuse the word "library" with "framework." The difference is quite simple: javascript frameworks provide structure to your code while libraries are generic sets of tools that aid in various tasks.

jQuery

jQuery is a fast, small, and feature-rich JavaScript library. It makes things like HTML document traversal and manipulation, event handling, animation, and Ajax much simpler with an easy-to-use API that works across a multitude of browsers. With a combination of versatility and extensibility, jQuery has changed the way that millions of people write JavaScript.

jQuery is a widely-used Javascript library that helps you code faster. Its purpose is to make it much easier to use JavaScript on your website. It takes a few lines in jQuery to accomplish many lines of Javascript code making it a "write less, do more" kind of JavaScript library.

  JQUERY                         IE9+
    
  $(el).fadeIn();                function fadeIn(el) {
                                    el.style.opacity = 0;
                                    var last = +new Date();
                                    var tick = function() {
                                     el.style.opacity = +el.style.opacity + (new Date() - last) / 400;
                                     last = +new Date();

                                     if (+el.style.opacity < 1) {
                                       (window.requestAnimationFrame && requestAnimationFrame(tick)) || setTimeout(tick, 16);
                                     }
                                   };

                                   tick();
                                 }

                                 fadeIn(el);

Rating: 4/5

React

React allows developers to create large web-applications that use data that can change over time, without reloading the page. It aims primarily to provide speed, simplicity and scalability. React processes only user interfaces in applications. This corresponds to View in the Model-View-Controller (MVC) template, and can be used in combination with other JavaScript libraries or frameworks in MVC, such as AngularJS.

React is an open-source Javascript library maintained by Facebook and Instagram. Invented by Jordan Walke on 2013, who was working on Facebook Ads at that time.

Following is a rudimentary example of how React can be used in html using JSX and the ECMAScript 2015 JavaScript syntax.

  <div id="myReactApp"></div>

  <script type="text/babel">
    class Greeter extends React.Component { 
      render() { 
        return <h1>{this.props.greeting}</h1>
      } 
    } 

    ReactDOM.render(<Greeter greeting="Hello World" />, document.getElementById('myReactApp'));
  </script>

Rating: 4/5

Lodash

A modern JavaScript utility library delivering modularity, performance & extras.

Created by John-David Dalton, Lodash is a JavaScript library which provides utility functions for common programming tasks using the functional programming paradigm. It draws most of its ideas from Underscore.js and now receives maintenance from the original contributors to Underscore.js.

It makes JavaScript easier by taking the hassle out of working with arrays, numbers, objects, strings, etc. Lodash’s modular methods are great for:

• Iterating arrays, objects, & strings
• Manipulating & testing values
• Creating composite functions

  Creates an array of elements split into groups the length of size. If array can't be split evenly, the final chunk will be the remaining elements.
  
   _.chunk(['a', 'b', 'c', 'd'], 2);
  // => [['a', 'b'], ['c', 'd']]

  _.chunk(['a', 'b', 'c', 'd'], 3);
  // => [['a', 'b', 'c'], ['d']]

Rating: 3/5