ecmascript-6-cheat-sheet.js

//
//   ECMAScript 6 Cheat Sheet
//
//////////////////////////////////////////////////////////////////////


//---------------------------------------------------------------
// Arrows (and this)
//---------------------------------------------------------------

// Expression bodies
var odds = evens.map(v => v + 1);
var nums = evens.map((v, i) => v + i);

// Statement bodies
nums.forEach(v => {
  if (v % 5 === 0)
    fives.push(v);
});


//---------------------------------------------------------------
// Modules
//---------------------------------------------------------------

// lib/math.js
export function sum(x, y) {
  return x + y;
}
export var pi = 3.141593;

// app.js
import * as math from "lib/math";
alert("2π = " + math.sum(math.pi, math.pi));

// otherApp.js
import {sum, pi} from "lib/math";
alert("2π = " + sum(pi, pi));

// lib/mathplusplus.js
export * from "lib/math";
export var e = 2.71828182846;
export default function(x) {
    return Math.exp(x);
}

// app.js
import exp, {pi, e} from "lib/mathplusplus";
alert("2π = " + exp(pi, e));


//---------------------------------------------------------------
// Classes
//---------------------------------------------------------------

export default class AnimPanel {
  constructor(options = {}) {
    // options:
    // \$el:             The jQuery selector that defines each description
    //                   (required)
    
    //
    // Internal Variables
    //

    this.options = $.extend(this.options, {
      name: 'Default Name'
    });
    this.foo = 'bar';

    _init();
  }
  

  //
  //   Private Methods
  //
  //////////////////////////////////////////////////////////////////////
  
  _init() {
    _addEventListeners();
  }

  _addEventListeners() {

  }


  //
  //   Public Methods
  //
  //////////////////////////////////////////////////////////////////////

  someMethod() {
    
  }

  static staticMethod() {
    
  }
}


//---------------------------------------------------------------
// Template Strings
//---------------------------------------------------------------

// Basic literal string creation
let text = `This is a pretty little template string.`

// Multiline strings
`In ES5 this is
 not legal.`

 // Interpolate variable bindings
 var name = "Bob", time = "today";
 `Hello ${name}, how are you ${time}?`

 // Unescaped template strings
 String.raw`In ES5 "\n" is a line-feed.`


 //---------------------------------------------------------------
 // Default + Rest + Spread
 //---------------------------------------------------------------

 function f(x, y=12) {
  // y is 12 if not passed (or passed as undefined)
  return x + y;
}
f(3) == 15

function f(x, ...y) {
  // y is an Array
  return x * y.length;
}
f(3, "hello", true) == 6

function f(x, y, z) {
  return x + y + z;
}
// Pass each elem of array as argument
f(...[1,2,3]) == 6


//---------------------------------------------------------------
// Let + Const
//---------------------------------------------------------------

function f() {
  {
    let x;
    {
      // okay, block scoped name
      const x = "sneaky";
      // error, const
      x = "foo";
    }
    // okay, declared with `let`
    x = "bar";
    // error, already declared in block
    let x = "inner";
  }
}