javascript.md

Indenting

• Never mix tabs and spaces
• Use 2 spaces for indenting

Data types

• Never use new to create a new variable. use [] for array, {} for object

// bad
var item = new Object(),
  array = new Array(),
  string = new String();

// good
var item = {},
  array = [],
  string = '';

Functions

• Always try to initiate variables in the first line

// bad
var foo = function () {
  function2();
  var a = 1;
  function3(a);
}
// good
var foo = function() {
  var a = 1;

  function2();
  function3(a);
}

• Group var statements

// bad
var foo = 1;
var bar = 2;

// good
var foo = 1,
  bar = 2;

Class

• Define private variables and private functions on top, add an empty line after private properties.

// bad
(function () {
  var obj = {};
  obj.foo = function () {
    bar();
  };
  i = 0;
  bar = function () {
    i += 1;
  };
  return obj;
}());

// good
(function () {
  var obj = {},
    i = 0,
    bar = function () {
      i += 1;
    };

  obj.foo = function () {
    bar();
  };
  return obj;
}());

Chaining

• Chain function calls on new lines

//bad
animate().now()
  .then();

//good
animate()
  .now()
  .then();

Naming Conventions

• file names in smaller case with _ seperator
• Variables in smaller case with words separated by _

//bad
var variableNotLikeThis;
var Variable_Not_Like_This;

//good
var variables_like_this;

• functions should be in lower camelcase

//bad
function IDoSomething() {
}

function i_do_something() {
}


//good
function iDoSomething() {
}

• Pseudo Classes should be in upper camelcase

//bad
var a = new this_is_an_object();
var b = new This_Is_An_Object();

//good
var a = new ThisIsAnObject();

Spacing and Empty lines

• Give necessary empty lines to make code more readable

//bad
/* global ButtonView */
'use strict';
var a = require('foo'),
    b = 1;
    c = function () {
        return 2;
    },
    d = function () {
        return 3
    };
a.operation();
return b;

//good
/* global ButtonView */

'use strict';

var a = require('foo'),
    b = 1,

    c = function () {
        return 2;
    },

    d = function () {
        return 3
    };

a.operation();

return b;

• break line on var chain if there will be a value assigned to it.

//bad
var a = foo(), b = bar(), c = 1, d, e;

//good
var a = foo(),
    b = bar(),
    c = 1,
    d, e;