可回味的js代码段

1，关于bind()-----

     var name="global";
    var person={
        name:"person",
        hello:function(sth){
                console.log(this.name+"say:"+sth);
        }
    };
    console.log(person.hello.bind(person)("jj"));

模拟bind()-----

Function.prototype.bind = function(){
  var fn = this, args = Array.prototype.slice.call(arguments), object = args.shift();
  return function(){
    return fn.apply(object,
      args.concat(Array.prototype.slice.call(arguments)));
  };
};

2,模拟new function

     function foo(age) {
         this.age = age;
     }

     foo.construct = function() {
         var o = {}, Constructor = foo;
         o.__proto__ = Constructor.prototype;
         // FF 支持用户引用内部属性 [[Prototype]]

         Constructor.apply(o, arguments);
         return o;
     };

     var obj1 = new foo(10);
     var obj2 = foo.construct(10);
     alert(obj2 instanceof foo);
     // true
     

3,数组去重

     Array.prototype.unique=function(){
         var newArr=[];
         var isExiteObj={};
         for(var i= 0,len=this.length;i<len;i++){
             if(!isExiteObj[this[i]]){
                 newArr.push(this[i]);
                 isExiteObj[this[i]]=1;
             }
         }
         return newArr;
     };
     var arr=[8,5,6,8,5,9];
     console.log(arr.unique());

4，删除数组----

 Array.prototype.remove = function(from, to) {
 var rest = this.slice((to || from) + 1 || this.length);
 this.length = from < 0 ? this.length + from : from;
 return this.push.apply(this, rest);
 };

5,求数组中的最大值，

var arr=[15,68,12,45,79];
var max=Math.max.apply(Math,arr);

6，判断对象时函数还是数组

function isArray(arr){
    var op=Object.prototype;
    if(op.toString.call(arr) == "[object Array]"){
        return true;
    }else{
        return false;
    }

}

function isFunction(fn){
    var op=Object.prototype;
    if(op.toString.call(fn) == "[object Function]"){
        return true;
    }else{
        return false;
    }

}