数组操作

 1 Array.prototype.unique1 = function(arr) {
 2   var
 3     i,
 4     length = this.length,
 5     mapArray = [],
 6     hash = {};
 7   for (i = 0; i < length; i += 1) {
 8     !hash[this[i]] && (
 9         hash[this[i]] = true,         
10         mapArray.push(this[i])
11     );
12   }
13   if(arr){
14     for(i = 0, length = arr.length; i < length; i += 1) {
15       !hash[arr[i]] && (
16         hash[arr[i]] = true,
17         mapArray.push(arr[i])
18       );
19     }
20   }
21   return mapArray;
22 };
23 Array.prototype.unique2 = function() {
24   var 
25     i,
26     length = this.length,
27     mapArray = [];
28   this.sort();
29   for (i = 0; i < length; i += 1){
30     this[i] != this[i + 1] && mapArray.push(this[i]);
31   }
32   return mapArray;
33 }
34 Array.prototype.unique3 = function() {
35   var
36     i,
37     length = this.length;
38     mapArray = [];
39   for (i = 0; i < length; i += 1){
40     mapArray.indexOf(this[i]) == -1 && mapArray.push(this[i]);
41   }
42   return mapArray;
43 };
44 Array.prototype.unique4 = function() {
45   var 
46     i,
47     length = this.length;
48     mapArray = [this[0]];
49   for (i = 1; i < length; i +=1) {
50     this.indexOf(this[i]) == i && mapArray.push(this[i]);
51   }
52   return mapArray;
53 }

 1 function reserve(arr1, arr2, mode) {
 2   var
 3     i,
 4     length,
 5     key,
 6     mapArray = [],
 7     hash = {};
 8   for(i = 0, length = arr2.length; i < length; i += 1) {
 9     !hash[arr2[i]] && (
10       hash[arr2[i]] = true,
11       mapArray.push(arr2[i])
12     );
13   }
14   arr2 = mapArray;
15   mapArray = [];
16   hash = {};
17   for(i = 0, length = arr1.length; i < length; i += 1) {
18     hash[arr1[i]] = true;
19   }
20   for(i = 0, length = arr2.length; i < length; i += 1) {
21     if(mode) {
22       hash[arr2[i]] && mapArray.push(arr2[i]);
23     } else {
24       hash[arr2[i]] ? delete hash[arr2[i]] : mapArray.push(arr2[i]);
25       for(key in hash) {
26         if(hash.hasOwnProperty(key)) {
27           mapArray.push(key);
28         }
29       }
30     }
31   }
32   return mapArray;
33 }

 1 /*升序*/
 2 Array.sort();
 3 /*降序*/
 4 array = array.sort( function( a, b ) { return b - a } );
 5 /*乱序*/
 6 array = array.sort( function() { return Math.random() - 0.5 } );
 7 /* true 升序  false 降序*/
 8 Array.prototype.bubble = function(mode) {
 9   var
10     i,
11     j,
12     yes,
13     value,
14     length = this.length;
15   for(i = 0; ;i += 1) {
16     yes = true;
17     for(j = 0; j < length; j += 1) {
18         if (mode){
19             this[j] > this[j + 1] && (
20                 value = this[j + 1],
21                 this[j + 1] = this[j],
22                 this[j] = value,
23                 yes = false
24             );
25         } else {
26             this[j] < this[j + 1] && (
27                 value = this[j + 1],
28                 this[j + 1] = this[j],
29                 this[j] = value,
30                 yes = false
31             ); 
32         }
33     }
34     if(yes) return this;
35   }
36 };
37 /*乱序*/
38 Array.prototype.shuffle = function() {
39   var
40     j,
41     x,
42     i = this.length;
43   for(; i;) {
44     j = parseInt(Math.random() * i);
45     x = this[--i];
46     this[i] = this[j];
47     this[j] = x;
48   };
49   return this;
50 };

1 /*内置方法*/
2 var arr = arr1.concat(arr2);
3 /*优化*/
4 var arr = Array.prototype.push.call(arr1,arr2);
5 /*或者*/
6 arr1.push.call(arr1,arr2);

1 /*减小数组长度*/
2 var 
3   arr = [1, 2, 3, 4, 5, 6, 7];
4   console.log(arr);[1, 2, 3, 4, 5, 6, 7];
5   arr.length = 3;
6   console.log(arr);//[1, 2, 3]

 1 var arr, array = [ 1, 2, 3, 4, 5, 6 ];
 2 arr = array.slice();
 3 console.log( arr ); //[ 1, 2, 3, 4, 5, 6 ]
 4 arr = array.slice( 2, 5 );
 5 console.log( arr ); //[ 3, 4, 5 ]
 6 arr = array.slice( -2, 5 );
 7 console.log( arr ); //[ 5 ]
 8 arr = array.slice( -2, -1 );
 9 console.log( arr ); //[  ]
10 arr = array.slice( -3 );
11 console.log( arr ); //[ 4, 5, 6 ]

 1 javscript 中数组类型分两种，原始类型、对象类型。都可以用浅克隆。除了对象类型中的对象得用深度克隆。
 2 function clone(object){
 3   var 
 4     key,
 5     newObj,
 6     obj = Object.prototype.toString.call(object).slice(8,-1);
 7   if(obj !== ‘Object‘){
 8     return newObj = object;
 9   } else if (window.JSON) {
10     newObj = JSON.stringify(object);
11     newObj = JSON.parse(newObj);
12     return newObj;
13   } else {
14     for(key in object){
15       newObj[key] = object[key];
16     }
17     return newObj;
18   }
19 }