js func

func.js

//方法调用模式
var obj = {
    val: 0,
    inc: function(i) {
        this.val += i;            
    }
};
console.log(obj.val);
obj.inc(2);
obj.inc(2);
console.log(obj.val);

// 函数调用模式
var add = function(a,b) {
    return a + b;
};
console.log(add(1,4));
obj.double = function () {
    var that = this;
    var helper = function() {
        that.val = add(that.val, that.val);        
    };
    helper();
};
obj.val = 5;
obj.double();
console.log(obj.val);

// 构造器调用
var Q = function(str) {
    this.status = str;
};
Q.prototype.getStatus = function() {
    return this.status;
};
var myQ = new Q('haha');
​console.log(myQ.getStatus());

// //avoid this..
// var yourQ = Q('haha');
// console.log(yourQ.getStatus());

// apply调用模式
var array = [3,4];
console.log(add.apply(null,array));
console.log(add.call(null,3,4));

var myStatus = {
    status: 'ok..'
};
console.log(Q.prototype.getStatus.apply(myStatus));
​

Function.prototype.method = function(name, func) {
    this.prototype[name] = func;
    return this;
};

Array.method('reduce', function(f, value) {
    for (var i = 0; i < this.length; i++) {
        value = f(this[i], value);
    };
    return value;
});

var add = function(a, b) {
    return a + b;
};
var mult = function(a, b) {
    return a * b;
};

var data = [1, 2, 3, 4, 5];
var sum = data.reduce(add, 0);
var mult = data.reduce(mult, 1);
console.log('sum: ' + sum);
console.log('mult: ' + mult);

data.total = function() {
    return this.reduce(add, 0);
};
console.log('total: ' + data.total());​