# Web前端编码规范

例：my-project

静态资源目录命名
例：js, css, img, json

参照项目命名规则。
例：index.js

参照项目命名规则。
例：index.scss

参照项目命名规则。
例：index.html

var x = 1,
    y = 1;
if (x < y) {
    x += 10;
} else {
    x += 1;
}

/* var declaration */
var x = 1;
/* expression statement */
x++;
/* do-while */
do {
    x++;
} while (x < 10);

// not good
var a = {
    b :1
};
// good
var a = {
    b: 1
};
// not good
++ x;
y ++;
z = x?1:2;
// good
++x;
y++;
z = x ? 1 : 2;
// not good
var a = [ 1, 2 ];
// good
var a = [1, 2];
// not good
var a = ( 1+2 )*3;
// good
var a = (1 + 2) * 3;
// no space before '(', one space before '{', one space between function parameters
var doSomething = function(a, b, c) {
    // do something
};
// no space before '('
doSomething(item);
// not good
for(i=0;i<6;i++){
    x++;
}
// good
for (i = 0; i < 6; i++) {
    x++;
}

// need blank line after variable declaration
var x = 1;
// not need blank line when variable declaration is last expression in the current block
if (x >= 1) {
    var y = x + 1;
}
var a = 2;
// need blank line before line comment
a++;
function b() {
    // not need blank line when comment is first line of block
    return a;
}
// need blank line after blocks
for (var i = 0; i < 2; i++) {
    if (true) {
        return false;
    }

    continue;
}
var obj = {
    foo: function() {
        return 1;
    },

    bar: function() {
        return 2;
    }
};
// not need blank line when in argument list, array, object
func(
    2,
    function() {
        a++;
    },
    3
);
var foo = [
    2,
    function() {
        a++;
    },
    3
];
var foo = {
    a: 2,
    b: function() {
        a++;
    },
    c: 3
};

// not good
var a = {
    b: 1
    , c: 2
};

x = y
    ? 1 : 2;
// good
var a = {
    b: 1,
    c: 2
};

x = y ? 1 : 2;
x = y ?
    1 : 2;
// no need line break with 'else', 'catch', 'finally'
if (condition) {
    ...
} else {
    ...
}
try {
    ...
} catch (e) {
    ...
} finally {
    ...
}
// not good
function test(){
    ...
}
// good
function test() {
    ...
}
// not good
var a, foo = 7, b,
    c, bar = 8;
// good
var a,
    foo = 7,
    b, c, bar = 8;

// not good
var a = {
    b: 1
    , c: 2
};

x = y
    ? 1 : 2;
// good
var a = {
    b: 1,
    c: 2
};

x = y ? 1 : 2;
x = y ?
    1 : 2;
// no need line break with 'else', 'catch', 'finally'
if (condition) {
    ...
} else {
    ...
}
try {
    ...
} catch (e) {
    ...
} finally {
    ...
}
// not good
function test(){
    ...
}
// good
function test() {
    ...
}
// not good
var a, foo = 7, b,
    c, bar = 8;
// good
var a,
    foo = 7,
    b, c, bar = 8;

if (condition) {
    // if you made it here, then all security checks passed
    allowed();
}

var zhangsan = 'zhangsan'; // one space after code

/*
 * one space after '*'
 */
var x = 1;

/**
 * @func
 * @desc 一个带参数的函数
 * @param {string} a - 参数a
 * @param {number} b=1 - 参数b默认值为1
 * @param {string} c=1 - 参数c有两种支持的取值</br>1—表示x</br>2—表示xx
 * @param {object} d - 参数d为一个对象
 * @param {string} d.e - 参数d的e属性
 * @param {string} d.f - 参数d的f属性
 * @param {object[]} g - 参数g为一个对象数组
 * @param {string} g.h - 参数g数组中一项的h属性
 * @param {string} g.i - 参数g数组中一项的i属性
 * @param {string} [j] - 参数j是一个可选参数
 */
function foo(a, b, c, d, g, j) {
    ...
}

// not good
var x = "test";
// good
var y = 'foo',
    z = '<div id="test"></div>';

var thisIsMyName;
var goodID;
var reportURL;
var AndroidVersion;
var iOSVersion;
var MAX_COUNT = 10;
function Person(name) {
    this.name = name;
}
// not good
var body = $('body');
// good
var $body = $('body');

// no space before '(', but one space before'{'
var doSomething = function(item) {
    // do something
};
function doSomething(item) {
    // do something
}
// not good
doSomething (item);
// good
doSomething(item);
// requires parentheses around immediately invoked function expressions
(function() {
    return 1;
})();
// not good
[1, 2].forEach(function x() {
    ...
});
// good
[1, 2].forEach(function() {
    ...
});
// not good
var a = [1, 2, function a() {
    ...
}];
// good
var a = [1, 2, function() {
    ...
}];
// use ', ' between function parameters
var doSomething = function(a, b, c) {
    // do something
};

// not good
var a = {
    'b': 1
};

var a = {b: 1};

var a = {
    b: 1,
    c: 2,
};
// good
var a = {
    b: 1,
    c: 2
};

if, else,for, while, do, switch, try, catch, finally, with。
// not good
if (condition)
    doSomething();
// good
if (condition) {
    doSomething();
}

// not good
function test(a, b) {
    if (b === null) {
        // not mean b is not supply
        ...
    }
}
var a;
if (a === null) {
    ...
}
// good
var a = null;
if (a === null) {
    ...
}

// not good
if (a == 1) {
    a++;
}
// good
if (a === 1) {
    a++;
}
// good
for (key in obj) {
    if (obj.hasOwnProperty(key)) {
        // be sure that obj[key] belongs to the object and was not inherited
        console.log(obj[key]);
    }
}
// not good
Array.prototype.count = function(value) {
    return 4;
};
// not good
var x = 1;
function test() {
    if (true) {
        var x = 0;
    }

    x += 1;
}
// not good
function test() {
    console.log(x);

    var x = 1;
}
// not good
new Person();
// good
var person = new Person();
// not good
delete(obj.attr);
// good
delete obj.attr;
// not good
if (a = 10) {
    a++;
}
// not good
var a = [1, , , 2, 3];
// not good
var nums = [];
for (var i = 0; i < 10; i++) {
    (function(i) {
        nums[i] = function(j) {
            return i + j;
        };
    }(i));
}
// not good
var singleton = new function() {
    var privateVar;

    this.publicMethod = function() {
        privateVar = 1;
    };

    this.publicMethod2 = function() {
        privateVar = 2;
    };
};

// not good
var a   = 1;
function Person() {
    // not good
    var me = this;

    // good
    var _this = this;

    // good
    var that = this;

    // good
    var self = this;
}
// good
switch (condition) {
    case 1:
    case 2:
        ...
        break;
    case 3:
        ...
    // why fall through
    case 4
        ...
        break;
    // why no default
}
// not good with empty block
if (condition) {

}