Recommended coding standards

The following are the coding standards that the Cocos Creator development team use. They are included in the manual for game developers` and tool developers' reference.

Naming standards

• When we name the variables, functions and living examples, we use camelCase nomenclature

  // bad
  var FOOBar = {};
  var foo_bar = {};
  function FOOBar () {}
  
  // good
  var fooBar = {};
  function fooBar () {}
  

• When we name types or modules, we use PascalCase nomenclature

  // bad
  var foobar = cc.Class({
      foo: 'foo',
      bar: 'bar',
  });
  var foobar = require('foo-bar');
  
  // good
  var FooBar = cc.Class({
      foo: 'foo',
      bar: 'bar',
  });
  var FooBar = require('foo-bar');
  

• Use underscores _ when naming private attributes

  // bad
  this.__firstName__ = 'foobar';
  this.firstName_ = 'foobar';
  
  // good
  this._firstName = 'foobar';
  

• We use dash nomenclature for files

  // bad
  fooBar.js
  FooBar.js
  
  // good
  foo-bar.js
  

Grammar standards

• Use {} to create an object

  // bad
  var obj = new Object();
  
  // good
  var obj = {};
  

• Use [] to create an array

  // bad
  var array = new Array();
  
  // good
  var array = [];
  

• Try your best to use single quotation marks '' to define a string in js code

  // bad
  var str = "Hello World";
  
  // good
  var str = 'Hello World';
  

• When defining multi-lines string, try your best to use +

  // bad
   const errorMessage = 'This is a super long error that was thrown out because of Batman. When you stop to think about how Batman had anything to do with this, you would get nowhere fast.';
  
   // bad
   const errorMessage = 'This is a super long error that was thrown out because \
   of Batman. When you stop to think about how Batman had anything to do \
   with this, you would get nowhere \
   fast.';
  
   // good
   const errorMessage = 'This is a super long error that was thrown out because ' +
     'of Batman. When you stop to think about how Batman had anything to do ' +
     'with this, you would get nowhere fast.';
  

• Use === and !== rather than == and !=.

Grammar standards

• Choose quadruple spacing or double spacing for indentation according to your own habits and the primary code writer's format.

  // bad
  function() {
  ∙var name;
  }
  
  // very bad
  function() {
  ∙∙<tab>∙∙var name;
  }
  
  // good
  function() {
  ∙∙var name;
  }
  
  // good
  function() {
  ∙∙∙∙var name;
  }
  

• Try to put { and the expression in the same line

  // bad
  if ( isFoobar )
  {
  }
  
  // good
  if ( isFoobar ) {
  }
  
  // bad
  function foobar()
  {
  }
  
  // good
  function foobar() {
  }
  
  // bad
  var obj =
  {
      foo: 'foo',
      bar: 'bar',
  }
  
  // good
  var obj = {
      foo: 'foo',
      bar: 'bar',
  }
  

• Put a space before {

  // bad
  function test(){
      console.log('test');
  }
  
  // good
  function test() {
      console.log('test');
  }
  
  // bad
  dog.set('attr',{
      age: '1 year',
      breed: 'Bernese Mountain Dog',
  });
  
  // good
  dog.set('attr', {
      age: '1 year',
      breed: 'Bernese Mountain Dog',
  });
  

• Please put a space before ( of the logic state expressions ( if, while )

   // bad
   if(isJedi) {
       fight ();
   }
  
   // good
   if (isJedi) {
       fight();
   }
  

• Please put a space between operators

  // bad
  var x=y+5;
  
  // good
  var x = y + 5;
  

• Put a space between Block definitions

  // bad
  if (foo) {
      return bar;
  }
  return baz;
  
  // good
  if (foo) {
      return bar;
  }
  
  return baz;
  
  // bad
  const obj = {
      foo() {
      },
      bar() {
      },
  };
  return obj;
  
  // good
  const obj = {
      foo() {
      },
  
      bar() {
      },
  };
  
  return obj;
  
  // bad
  const arr = [
      function foo() {
      },
      function bar() {
      },
  ];
  return arr;
  
  // good
  const arr = [
      function foo() {
      },
  
      function bar() {
      },
  ];
  
  return arr;
  

• Do not use a comma to define

  // bad
  var story = [
        once
      , upon
      , aTime
  ];
  
  // good
  var story = [
      once,
      upon,
      aTime,
  ];
  
  // bad
  var hero = {
        firstName: 'Ada'
      , lastName: 'Lovelace'
      , birthYear: 1815
      , superPower: 'computers'
  };
  
  // good
  var hero = {
      firstName: 'Ada',
      lastName: 'Lovelace',
      birthYear: 1815,
      superPower: 'computers',
  };
  

Reference

airbnb/es5