ECMAScript History

ES2015 features to use today

1. let declarations
2. template strings
3. object methods
4. fat arrow functions
5. destructuring

Let

// var: function scoping, variables are hoisted
var array = [];
console.log(i); // prints undefined
for (var i = 0; i < 10; i++) {
  array.push(Math.random());
}
console.log(i);  // prints 10

// let: block scoping, no hoisting
let array = [];
console.log(i);  // ReferenceError
for (let i = 0; i < 10; i++) {
  array.push(Math.random());
}
console.log(i);  // ReferenceError

Template Strings

var pageNumber = "( " + getCount() + " / " + pageTotal + " )";

let pageNumber = `( ${getCount()} / ${pageTotal} )`;

Methods

var Duck = Backbone.Model.extend({
  name: function name() {
    return "duck";
  },
  sound: function sound() {
    return "quack";
  }
});

let Duck = Backbone.Model.extend({
  name() {
    return "duck";
  },
  sound() {
    return "quack";
  }
});