一些通用的javascript方法

2015-1-30新增：

javascript常用方法函数收集  http://www.css88.com/archives/5180

一些通用的javascript方法：

function range(start, end) {
    var result = [];
 
    if(typeof end === 'undefined') {
        end = start;
        start = 0;
    }
    for(;start < end; start++) {
        result.push(start);
    }
 
    return result;
}
undefined
range(10)
[0, 1, 2, 3, 4, 5, 6, 7, 8, 9]
range(4)
[0, 1, 2, 3]
range(2)
[0, 1]

一个array的shuffle打乱函数

Array.prototype.randomEach = function(func) {
    if (typeof func != "function") {
        throw new TypeError();
    }
 
    var len = this.length,
        indexes = range(len);
 
    while(len) {
        var cursor = Math.floor(Math.random() * (len--));
        if(func(this[indexes[cursor]]) === false) {
            break;
        }
    }
};

对比下常规的shuffle函数

function shuffle(array) {
  var currentIndex = array.length
    , temporaryValue
    , randomIndex
    ;
 
  // While there remain elements to shuffle...
  while (0 !== currentIndex) {
 
    // Pick a remaining element...
    randomIndex = Math.floor(Math.random() * currentIndex);
    currentIndex -= 1;
 
    // And swap it with the current element.
    temporaryValue = array[currentIndex];
    array[currentIndex] = array[randomIndex];
    array[randomIndex] = temporaryValue;
  }
 
  return array;
}
var arr = [2, 11, 37, 42];
shuffle(arr);
console.log(arr);shuffle(arr);
console.log(arr);shuffle(arr);
console.log(arr);
[42, 2, 11, 37, confound: function]
[2, 11, 37, 42, confound: function]
[2, 37, 11, 42, confound: function]

下面还是一个shuffle函数

Array.prototype.confound = function () {
    this.sort(function () {
        return Math.random() - 0.5;
    });
};
a
["c", "b", "a"]
a.confound();
undefined
a
["b", "a", "c"]

下面还是一个shuffle函数

Array.prototype.confound = function () {
    this.sort(function () {
        return Math.random() - 0.5;
    });
};
a
["c", "b", "a"]
a.confound();
undefined
a
["b", "a", "c"]

克隆object的方法

function _shadowClone(obj){
    var result = {};
    for(var key in obj){
        if(obj.hasOwnProperty(key)){
            result[key] = obj[key];
        }
    }
    return result;
}

Json---》Array

function json2array(json){
    var result = [];
    var keys = Object.keys(json);
    keys.forEach(function(key){
        result.push(json[key]);
    });
    return result;
}
//example
json2array({a:1,b:2});
[1, 2]
//more complex example
json2array({20131013: 66, 20131014: 198, 20131015: 253, 20131016: 352, 20131017: 293, 20131018: 277, 20131019: 111, 20131020: 91, 20131021: 255, 20131022: 256, 20131023: 293, 20131024: 390, 20131025: 401, 20131026: 117, 20131027: 45, 20131028: 54, 20131029: 59, 20131030: 66, 20131031: 109, 20131101: 32});
[66, 198, 253, 352, 293, 277, 111, 91, 255, 256, 293, 390, 401, 117, 45, 54, 59, 66, 109, 32]

Array---》String

var a = [{"obj1":"phpgcs"}, {"obj2":"ganiks"}]
console.log(a);
//[Object, Object]
JSON.stringify(a)
//"[{"obj1":"phpgcs"},{"obj2":"ganiks"}]"

String---》Array

"1,2".split(",").map(Number);
[1, 2]
"1,2".split(",");
["1", "2"]
JSON.parse("["+"1,2"+"]");
[1, 2]

Object---》Json

//php print_r($response);
 
.post(url, params, function(data){
    console.log(data);//data并不是规范的JSON格式的
    data = $.parseJSON(data);
    console.log(data);
});<br>//这里如果直接用.getJSON方法获取ajax数据则直接就是规范的JSON数据

Array---》Object

function toObject(arr) {
  var rv = {};
  for (var i = 0; i < arr.length; ++i)
    rv[i] = arr[i];
  return rv;
}
Your array already is more-or-less just an object, but arrays do have some "interesting" and special behavior with respect to integer-named properties. The above will give you a plain object.
edit oh also you might want to account for "holes" in the array:
 
function toObject(arr) {
  var rv = {};
  for (var i = 0; i < arr.length; ++i)
    if (arr[i] !== undefined) rv[i] = arr[i];
  return rv;
}

参考：

http://phpgcs.com/2013/10/31/javascript-tricks-collection.html

http://stackoverflow.com/questions/17684921/sort-json-object-in-javascript

http://stackoverflow.com/questions/1069666/sorting-javascript-object-by-property-value

http://stackoverflow.com/questions/4215737/convert-array-to-object