js:方法1. 数组

Array.every()###

array.every(f); array.every(f, o); f(array[i], i, array)

[1,2,3].every(function(x) { return x < 5; }) // => true
[1,2,3].every(function(x) { return x < 3; }) // => false
[].every(function(x) { return false; }); // => true: always true for []

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

Array.some()###

array.some(predicate); array.some(predicate, o)

[1,2,3].some(function(x) { return x > 5; }) // => false: no elts are > 5
[1,2,3].some(function(x) { return x > 2; }) // => true: some elts are > 3
[].some(function(x) { return true; }); // => false: always false for []

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

Array.filter()

array.filter(f); array.filter(f, o); f(array[i], i, array)

[1,2,3].filter(function(x) { return x > 1; }); // => [2,3]

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

Array.map()

array.map(f); array.map(f, o); a[i] = f(array[i], i, array)

[1,2,3].map(function(x) { return x * 2; }); // => [2,4,6]

//
if(!Array.prototype.map) {
	Array.prototype.map  = function (func /*,thisp*/) {
		var len = this.length >>> 0;
		if(typeof func !== '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] = func.call(thisp,this[i],i,this);
			}
		}
		return res;
	}
}

Array.forEach()

array.forEach(f); array.forEach(f, o); f(array[i], i, array)

var a = [1,2,3];
a.forEach(function(x,i,a) { a[i]++; }); // a is now [2,3,4]

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

Array.reduce()/ Array.reduceRight()

array.reduce(f); array.reduce(f, initial)

[1,2,3,4].reduce(function(x,y) { return x*y; }) // => 24: ((1*2)*3)*4

Array.concat()###

array.concat(value, ...)

var a = [1,2,3];
a.concat(4, 5) // => [1,2,3,4,5]
a.concat([4,5]); // => [1,2,3,4,5]
a.concat([4,5],[6,7]) // => [1,2,3,4,5,6,7]
a.concat(4, [5,[6,7]]) // => [1,2,3,4,5,[6,7]]

Array.indexOf() /Array.lastIndexOf()

array.indexOf(value); array.indexOf(value, start)

['a','b','c'].indexOf('b') // => 1
['a','b','c'].indexOf('d') // => -1
['a','b','c'].indexOf('a',1) // => -1

//
if(!Array.prototype.indexOf) {
	Array.prototype.indexOf  = function (elt /*,from*/) {
		var len = this.length >>> 0,
		   from = Number(arguments[1]) || 0;
		from = (from < 0)
		? Math.ceil(from)
		: Math.floor(from);
		if(from < 0) {
			from += len;
		}
		for(; from < len; ++from) {
			if(from in this && this[from] === elt)
				return from;
		}
		return -1;
	}
}

Array.join()###

array.join(); array.join(separator)

a = new Array(1, 2, 3, "testing");
s = a.join("+"); // s is the string "1+2+3+testing"

Array.slice()###

array.slice(start, end)

var a = [1,2,3,4,5];
a.slice(0,3); // Returns [1,2,3]
a.slice(3); // Returns [4,5]
a.slice(1,-1); // Returns [2,3,4]
a.slice(-3,-2); // Returns [3]; buggy in IE 4: returns [1,2,3]

Array.splice()###

array.splice(start, deleteCount, value, ...)

var a = [1,2,3,4,5,6,7,8]
a.splice(1,2); // Returns [2,3]; a is [1,4]
a.splice(1,1); // Returns [4]; a is [1]
a.splice(1,0,2,3); // Returns []; a is [1 2 3]

Array.reverse()###

array.reverse()

a = new Array(1, 2, 3); // a[0] == 1, a[2] == 3;
a.reverse(); // Now a[0] == 3, a[2] == 1;

Array.sort()###

array.sort(); array.sort(orderfunc)

// An ordering function for a numerical sort
function numberorder(a, b) { return a - b; }
a = new Array(33, 4, 1111, 222);
a.sort(); // Alphabetical sort: 1111, 222, 33, 4
a.sort(numberorder); // Numerical sort: 4, 33, 222, 1111

Array.push()/ Array.pop()###

array.push(value, ...)； array.pop()

var stack = []; // stack: []
stack.push(1, 2); // stack: [1,2] Returns 2
stack.pop(); // stack: [1] Returns 2
stack.push([4,5]); // stack: [1,[4,5]] Returns 2
stack.pop() // stack: [1] Returns [4,5]
stack.pop(); // stack: [] Returns 1

Array.shift()###

array.shift()

var a = [1, [2,3], 4]
a.shift(); // Returns 1; a = [[2,3], 4]
a.shift(); // Returns [2,3]; a = [4]

Array.unshift()###

array.unshift(value, ...)

var a = []; // a:[]
a.unshift(1); // a:[1] Returns: 1
a.unshift(22); // a:[22,1] Returns: 2
a.shift(); // a:[1] Returns: 22
a.unshift(33,[4,5]); // a:[33,[4,5],1] Returns: 3