Choosing a javascript framework

I gave a talk recently on why a client might want to adopt a javascript framework. They were writing their own presentation layer, and were debating adding either Angular or React. Here are the notes for my presentation.

Note: Excuse the contrived "datas" examples everywhere. I modified it to keep the company secret.

Benefits of using a widely-adopted framework

  • Less time spent teaching new hires
  • Do more, write less
  • Maintainability & knowledge sharing
  • Community support for questions
  • Plugins
  • Testing
  • 3rd party tools are well vetted for bugs, speed
  • reduce AJAX calls, reduce number of trips, potential failure
    • share data between views
    • dynamic templates
    • faster page transitions
  • would make transitioning to single-page app easy (if/when)

What Angular does well

  • Dependency injection
  • Highly testable
  • Separation of concerns
  • Component/module pattern; app is a composition of modules
  • Two-way data binding
  • Declarative HTML
  • Templates rendering to JS strings behind the scenes
  • Great ecosystem

https://angular.io/docs/js/latest/quickstart.html

What Angular doesn’t do well

  • Keep view and controller close
  • Different provider types are functions that return functions
  • Doesn’t feel like writing Javascript
  • Upgrade path to version 2.0

What React does well

  • View and controller code in one file
  • Promotes uni-directional data flow
  • Follows existing javascript patterns
  • Component-based
  • Can be easily dropped into any existing project

https://facebook.github.io/react/docs/why-react.html

What React doesn’t do well

  • Unstable ecosystem
  • Being the “V” in MVC is limiting

Other JS frameworks

  • Polymer & web components
  • Ember (testing is hard!)
  • Backbone

Meh.

Plain JS page

$.get(/api/datas’)
.done(function(response){
       var ul = $(<ul class=“datas”>);
  $.each(response.datas, function(data){
    ul.append($(<li class=“data”>, data.name + data.cashMoney));
  });
  document.body.appendChild(ul);
});

$(.new-data-button’).click(function(event){
  event.preventDefault();
  event.stopPropagation();
  $.post(/api/datas’).done(function(response){
    $(.datas’).append($(<li class=“data”>,
    data.name + data.cashMoney);
  });
});

React version

import React from ‘react’;

class Datas extends React.Component {

  addNewData () {
    $.post(/api/datas’).done(function(response){
      this.setState({datas: response.datas});
    });
  }

  render () {
    var datas = this.state.datas.map(function(data){
      return <li className=“data”>{data.name} {data.cashMoney}</li>;
    });
    return (
      <section>
        <ul className=“datas”>
          {datas}
        </ul>
        <button onClick={addNewData}>Add new data</button>
      </section>
    )
  }
}

React.render(<Datas />, document.body);


Angular version

<body ng-app=“app”>
  <datas></datas>
</body>


<!-- directive template -->
<section>
  <ul class=“datas”>
    <li ng-repeat=“data in DatasCtrl.datas”>{{data.name}} {{data.cashMoney}}</li>
  </ul>
  <button ng-click=“DatasCtrl.addNewData(data)”>Add new data</button>
</section>
// app.js
angular.module(‘app’, [‘datas’]);

// data-module.js
angular.module(‘datas’, [])
  .directive(function() {
    return {
      templateUrl: ‘app/views/directives/datas.html’,
      restrict: ‘E’,
      replace: true,
      controller: ‘DatasController’,
      controllerAs: ‘DatasCtrl
    }
})
.controller(‘DatasController’, function(DatasResource){
  this.datas = DatasResource.get();

  this.addNewData = function(data){
    this.datas.push(data);
    new DatasResource(data).save();
  };
})
.factory(‘DatasResource’, function($resource) {
  return $resource(/api/datas’);
})

Should you adopt one?

Give it one, both, or another a try. Make the scope of the work small.

Choose one if you all enjoy writing in it, and it makes your lives easier.