javascript Array数组对象的扩展函数代码

(function(){
var YArray;

YArray = function(o,idx,arraylike){
var t = (arraylike) ? 2 : YArray.test(o),
l, a, start = idx || 0;
if (t) {
try {
return Array.prototype.slice.call(o, start); //借助Array原生方法来把aguments转换为JS数组
} catch(e) {
a = [];
l = o.length;
for (; start<l; start++) {
a.push(o[start]);
}
return a;
}
} else {
return [o];
}

}

YArray.test = function(o){
var r = 0;
if (o && (typeof o == 'object' ||typeof o == 'function')) {
if (Object.prototype.toString.call(o) === "[object Array]") {
r = 1;
} else {
try {
if (('length' in o) && !o.tagName && !o.alert && !o.apply) {
r = 2;
}
} catch(e) {}
}
}
return r;
}

YArray.each = (Array.prototype.forEach) ? //先检测浏览器是否已支持，若有则调用原生
function (a, f, o) {
Array.prototype.forEach.call(a || [], f, o || Y);
return YArray;
} :
function (a, f, o) {
var l = (a && a.length) || 0, i;
for (i = 0; i < l; i=i+1) {
f.call(o || Y, a[i], i, a);
}
return YArray;
};

YArray.hash = function(k, v) {
var o = {}, l = k.length, vl = v && v.length, i;
for (i=0; i<l; i=i+1) {
if (k[i]) {
o[k[i]] = (vl && vl > i) ? v[i] : true;
}
}

return o;
};

YArray.indexOf = (Array.prototype.indexOf) ?
function(a, val) {
return Array.prototype.indexOf.call(a, val);
} :
function(a, val) {
for (var i=0; i<a.length; i=i+1) {
if (a[i] === val) {
return i;
}
}
return -1; //寻找不到的情况
};

YArray.numericSort = function(a, b) {
return (a - b); //从小到大排序, return (b - a); 从大到小
};


YArray.some = (Array.prototype.some) ?
function (a, f, o) {
return Array.prototype.some.call(a, f, o);
} :
function (a, f, o) {
var l = a.length, i;
for (i=0; i<l; i=i+1) {
if (f.call(o, a[i], i, a)) {
return true;
}
}
return false;
};

})();

Array.apply(null,arguments);
[].slice.call(arguments,0);
[].splice.call(arguments,0,arguments.length);
[].concat.apply([],arguments);
...

a = [];
l = o.length;
for (; start<l; start++) {
a.push(o[start]);
}
return a;

YArray.each([1,2,3],function(item){
alert(item);// 执行了3次，1,2,3
});

YArray.some([3, 1, 2],function(el){
return el < 4;
})

if (!Array.prototype.every)
{
Array.prototype.every = function(fun /*, thisp*/)
{
var len = this.length >>> 0;
if (typeof fun != "function")
throw new TypeError();
var thisp = arguments[1];
for (var i = 0; i < len; i++)
{
if (i in this &&
!fun.call(thisp, this[i], i, this))
return false;
}
return true;
};
}

Array.prototype.filter = function (block /*, thisp */) { //过滤器 ，添加方便，进行判断过滤
var values = [];
var thisp = arguments[1];
for (var i = 0; i < this.length; i++)
if (block.call(thisp, this[i]))
values.push(this[i]);
return values;
};

var val= numbers.filter(function(t){
return t < 5 ;
})
alert(val);

Array.prototype.map = function(fun /*, thisp*/) {
var len = this.length >>> 0;
if (typeof fun != "function")
throw new TypeError();
var res = new Array(len);
var thisp = arguments[1];
for (var i = 0; i < len; i++) {
if (i in this)
res[i] = fun.call(thisp, this[i], i, this);
}
return res;
};

Array.prototype.reduce = function(fun /*, initial*/) {
var len = this.length >>> 0;
if (typeof fun != "function")
throw new TypeError();
if (len == 0 && arguments.length == 1)
throw new TypeError();
var i = 0;
if (arguments.length >= 2) {
var rv = arguments[1];
} else {
do {
if (i in this) {
rv = this[i++];
break;
}
if (++i >= len)
throw new TypeError();
} while (true);
}
for (; i < len; i++) {
if (i in this)
rv = fun.call(null, rv, this[i], i, this);
}
return rv;
};

Array.prototype.reduceRight = function(fun /*, initial*/) {
var len = this.length >>> 0;
if (typeof fun != "function")
throw new TypeError();
if (len == 0 && arguments.length == 1)
throw new TypeError();
var i = len - 1;
if (arguments.length >= 2) {
var rv = arguments[1];
} else {
do {
if (i in this) {
rv = this[i--];
break;
}
if (--i < 0)
throw new TypeError();
} while (true);
}
for (; i >= 0; i--) {
if (i in this)
rv = fun.call(null, rv, this[i], i, this);
}
return rv;
};

Array.prototype.toString = function () {
return this.join('');
};