风格规范

命名
- 变量命名，驼背法: Always
  
  functionNamesLikeThis, variableNamesLikeThis, ClassNamesLikeThis, EnumNamesLikeThis, methodNamesLikeThis, and SYMBOLIC_CONSTANTS_LIKE_THIS
- 缩写和短语用在命名的时候不以全大写形式出现 Preferred
```
getInnerHtml(), getXml(), XmlDocument
```
- 使用带名称的闭包 Preferred
```
req.on('end', function onEnd() {
  console.log('winning');
});
```
- Boolean变量以“is”开头 Preferred
- 初始化方法以“init”、“initialize”开头 Preferred
- 集合的命名必须是单词的复数形式 Always
- 记录数量的变量应该以“num”或“count”开头 Always
- 循环迭代变量应该以“i”, “j”, “k”依次命名 Always
尽量使用英文进行变量命名和代码注释 Preferred
Whitespace - 空白符
- 使用2个空格作为一个单位的缩进 Preferred
- 逗号后面必须跟随一个空格 Always
- 冒号必须前后均有一个空格 Always
- for循环语句的分好后方跟随一个空格 Always
- 分号之前没有空格 Always
- 函数调用的圆括号之前没有空格 Always
- 使用空行来将逻辑上相关的几行代码分组: Preferred
- 以下关键字不以空格结尾 Always
  - break
  - catch
  - continue
  - do
  - else
  - finally
  - for
  - function －如果是匿名函数，例如：
```
var foo = function(){};
```
  - if
  - return
  - switch
  - this
  - try
  - void
  - while
  - with
- 以下关键字后方必须有一个空格 Always
  - case
  - default
  - delete
  - function - 如果是函数声明, 例如：
```
function foo(){};
```
  - in
  - instanceof
  - new
  - throw
  - typeof
  - var
Getters Preferred
Setters Careful

嵌套闭包 Never

//wrong 
setTimeout(function() {
  client.connect(function() {
    console.log('losing');
  });
}, 1000);

重要的判断条件，要单独创建一个变量

var isAuthorized = (user.isAdmin() || user.isModerator());
if (isAuthorized) {
  console.log('winning');
}

自定义的toString方法

确保没有任何副作用

代码格式化

if语句的大括号: Always

if (something) {
  // ...
} else {
  // ...
}

数组和对象初始化: Always

var arr = [1, 2, 3];  // No space after [ or before ].
var obj = {a: 1, b: 2, c: 3};  // No space after { or before }.

多行字面量以2个空格打头，并以逗号结尾: Always

// Object initializer.
var inset = {
  top: 10,
  right: 20,
  bottom: 15,
  left: 12
};

// Array initializer.
this.rows_ = [
  '"Slartibartfast" <fjordmaster@magrathea.com>',
  '"Zaphod Beeblebrox" <theprez@universe.gov>',
  '"Ford Prefect" <ford@theguide.com>',
  '"Arthur Dent" <has.no.tea@gmail.com>',
  '"Marvin the Paranoid Android" <marv@googlemail.com>',
  'the.mice@magrathea.com'
];

字面量键值名称无需对齐: Preferred

CORRECT_Object.prototype = {
  a: 0,
  b: 1,
  lengthyName: 2
};

函数参数格式: Preferred

// Four-space, wrap at 80.  Works with very long function names, survives
// renaming without reindenting, low on space.
goog.foo.bar.doThingThatIsVeryDifficultToExplain = function(
    veryDescriptiveArgumentNumberOne, veryDescriptiveArgumentTwo,
    tableModelEventHandlerProxy, artichokeDescriptorAdapterIterator) {
  // ...
};

// Four-space, one argument per line.  Works with long function names,
// survives renaming, and emphasizes each argument.
goog.foo.bar.doThingThatIsVeryDifficultToExplain = function(
    veryDescriptiveArgumentNumberOne,
    veryDescriptiveArgumentTwo,
    tableModelEventHandlerProxy,
    artichokeDescriptorAdapterIterator) {
  // ...
};

// Parenthesis-aligned indentation, wrap at 80.  Visually groups arguments,
// low on space.
function foo(veryDescriptiveArgumentNumberOne, veryDescriptiveArgumentTwo,
             tableModelEventHandlerProxy, artichokeDescriptorAdapterIterator) {
  // ...
}

// Parenthesis-aligned, one argument per line.  Visually groups and
// emphasizes each individual argument.
function bar(veryDescriptiveArgumentNumberOne,
             veryDescriptiveArgumentTwo,
             tableModelEventHandlerProxy,
             artichokeDescriptorAdapterIterator) {
  // ...
}

if (veryLongFunctionNameA(
        veryLongArgumentName) ||
    veryLongFunctionNameB(
    veryLongArgumentName)) {
  veryLongFunctionNameC(veryLongFunctionNameD(
      veryLongFunctioNameE(
          veryLongFunctionNameF)));
}

传递匿名函数: Preferred

prefix.something.reallyLongFunctionName('whatever', function(a1, a2) {
  if (a1.equals(a2)) {
    someOtherLongFunctionName(a1);
  } else {
    andNowForSomethingCompletelyDifferent(a2.parrot);
  }
});

var names = prefix.something.myExcellentMapFunction(
    verboselyNamedCollectionOfItems,
    function(item) {
      return item.name;
    });

使用更多的缩进: Preferred

someWonderfulHtml = '' +
                    getEvenMoreHtml(someReallyInterestingValues, moreValues,
                                    evenMoreParams, 'a duck', true, 72,
                                    slightlyMoreMonkeys(0xfff)) +
                    '';

thisIsAVeryLongVariableName =
    hereIsAnEvenLongerOtherFunctionNameThatWillNotFitOnPrevLine();

thisIsAVeryLongVariableName = 'expressionPartOne' + someMethodThatIsLong() +
    thisIsAnEvenLongerOtherFunctionNameThatCannotBeIndentedMore();

someValue = this.foo(
    shortArg,
    'Some really long string arg - this is a pretty common case, actually.',
    shorty2,
    this.bar());

if (searchableCollection(allYourStuff).contains(theStuffYouWant) &&
    !ambientNotification.isActive() && (client.isAmbientSupported() ||
                                        client.alwaysTryAmbientAnyways())) {
  ambientNotification.activate();
}

二元和三元运算符: Preferred

var x = a ? b : c;  // All on one line if it will fit.

// Indentation +4 is OK.
var y = a ?
    longButSimpleOperandB : longButSimpleOperandC;

// Indenting to the line position of the first operand is also OK.
var z = a ?
        moreComplicatedB :
        moreComplicatedC;

可见性 @private and @protected: Preferred

  // File 1.

  /** @constructor */  
  AA_PublicClass = function() {
  };

  /** @private */    
  AA_PublicClass.staticPrivateProp_ = 1;

  /** @private */
  AA_PublicClass.prototype.privateProp_ = 2;

  /** @protected */  
  AA_PublicClass.staticProtectedProp = 31;

  /** @protected */  
  AA_PublicClass.prototype.protectedProp = 4;

使用JSDoc: Preferred