lushijie

;(function() {
    function MyModule() {
      // ...
    }
    var moduleName = MyModule;
    
    if (typeof module !== 'undefined' && typeof exports === 'object' && define.cmd) {
        module.exports = moduleName;
    } else if (typeof define === 'function' && define.amd === 'object' && define.amd) {
        define(function() {

lushijie

//undefined 与 null 返回false，其他返回true
function existy(x) {
    return x != null;
}

function truthy(x) {
    return (x !== false) && existy(x);
}

function doWhen(condtion, action) {

lushijie

function Foo(x, y, z, w) {
    var args = arguments;
    if (args.length < Foo.length) {
        return function() {
            var oldArgs = Array.prototype.slice.call(args);
            var newArgs = oldArgs.concat(Array.prototype.slice.call(arguments));
            return args.callee.apply(null,newArgs);
        }
    } else {
        return x + y - z * w;

lushijie

//1.数组求和
var arr = [1,2,3,4];
var total = arr.reduce(function(pre, cur, index, arr){
    //接受四个参数：初始值（或者上一次回调函数的返回值），当前元素值，当前索引，调用 reduce 的数组
    //arr.reduce(callback,[initialValue])
    return pre + cur;
})
console.log(total)
//2.把二维数组转换为json键值对
var relArray = [

lushijie

function onceWraper(func){
    return function(){
        if(func){
            var ret = func.apply(this,arguments);
            func = null;
            return ret;
        }else{
            console.log('非第一次运行不再执行');
            return;
        }

lushijie

function shareFunc(func){
    //初始化函数运行过程中依赖的变量
    //之前一般的方式是声明全局变量,程序的阅读与理解难度增加，全局变量容易受干扰
    var varWraper ={
        a:0
    }
    return function(){
        var args = [].slice.apply(arguments);
        args.push(varWraper);
        var ret = func.apply(this,args);

lushijie

$.debounce = function(fn, time, ctx) {
    var ret = 0;
    if( typeof time !== 'number' ) {
      ctx = time;
      time =  50;
    }
    time = time || 50;
    return function() {
      var args = [].slice.apply(arguments);
      // 注意是ctx的问题

lushijie

(function(i, s, o, g, r, a, m) {
	i['GoogleAnalyticsObject'] = r;
	i[r] = i[r] || function() {
		(i[r].q = i[r].q || []).push(arguments)
	}, i[r].l = 1 * new Date();
	a = s.createElement(o),
		m = s.getElementsByTagName(o)[0];
	a.async = 1;
	a.src = g;
	m.parentNode.insertBefore(a, m)

lushijie

var func = (function f(a) { 
    console.log(a); 
    return f; 
})('Hello World');

lushijie

function x() {
  console.log('x')
};
function y() {
  console.log('y')
};
var z = 3;
(z==3?x:y)();