js technic

AOP.js

var service = function(){
    console.log('task start...');
}
var test = (function(){
    var time_start;
    return {
        before: function(){
            time_start = (+new Date());
            console.log('cunting...');
        },
        after: function(){
            var end = (+new Date()) - time_start;
            console.log('counting stop：' + end);
        }
    }
})();
var aop = function(fn, proxy){
    proxy.before && proxy.before();
    fn();
    proxy.after && proxy.after();
}
aop(service, test);

apply-call-bind.js

var op = {a: 1};
var a = 2;

(function(){
	console.log(this.a);
})()  // 2

(function(){
    	console.log(this.a);
}()) // 2

(function(){
	console.log(this.a)
}.apply(op))

(function(){
  	console.log(this.a)
}).call(op)

(function(){
  	console.log(this.a);
}).bind(op)()  // 1

(function(){
    	console.log(this.a);
}.bind(op)()) // 1

(function(arg1, arg2){
  	console.log(this, arg1, arg2)
}).call(op, "ss", "sss")

(function(arg1, arg2){
	console.log(this, arg1, arg2)
}).apply(op, ["ss", "sss"])

setTimeout(function(arg){
	console.log(op, arg)
}.call(op, "ss"), 19, "sss")  // {a: 1} "ss"

chunk-function.js

var chunk = function(arr, process, count){
    setTimeout(function(){
        for(var i = 0; i < Math.min(count, arr.length); i++) {
            process(arr.shift());
        }
        if(arr.length > 0) {
            setTimeout(arguments.callee, 100);
        }
    }, 100);
}
chunk([1,2,3,4,5,6,7,8,9,10], function(x){console.log(x);}, 1)

closure-increment.js

var auto_increase = function(){
  var id=0;
  return function(){
    return ++id;
  }
}();
var increaser = (function(){
	var i = 0;
	var obj = {};
	obj.reset = function(){
		i = 0;
		console.log("reset", i);
	}
	obj.increase = function(){
		++i;
		console.log("increase", i);
	}
	return obj;
}())

// 1
auto_increase();
// 2
auto_increase();

// newbie
var gotop = function(){
    if(/firefox/i.test(navigator.userAgent)) {
        document.documentElement.scrollTop = 0;
    } else {
        document.body.scrollTop = 0;
    }
}
// veteran
var gotop = (function(){
    var isFF = /firefox/i.test(navigator.userAgent);
    var docEl = document[ isFF ? 'documentElement' : 'body' ];
    return function(){
        docEl.scrollTop = 0;
    }
})();

debounce-throttle.js

var getData = (function(){
    var onAjax = false;
    return function(callback){
        if(!onAjax) {
            onAjax = true;
            $.get('/xxx', function(data){
                callback(data);
                onAjax = false;
            });
        }
    }
})();
$(window).scroll(function(){
    if(bottom) {
        getData(render);
    }
});

// debounce
function _debounce(fn,wait){
    var timer = null;
    return function(){
        clearTimeout(timer)
        timer = setTimeout(()=>{
            fn()
        },wait)
    }
}

function _log(){
    console.log(1)
}
window.onscroll = _debounce(_log,500)

//throttle
function _throttle(fn,wait,time){
    var previous = null; //record previous time
    var timer = null;

    return function(){
        var now = +new Date();

        if(!previous) previous = now;
        //if the gap longer than the throttle, run actively
        if(now - previous > time){
            clearTimeout(timer);
            fn();
            previous = now;
        }else{
            clearTimeout(timer);
            timer = setTimeout(function(){
                fn();
            },wait);
        }
    }
}
function _log(){
    console.log(1)
}
window.onscroll = _debounce(_log,500,2000)

Dependency-injection.js

// Service container
var services = { 
    A: () => {console.log(1)}, 
    B: () => {console.log(2)},
    C: () => {console.log(3)}
}
// Service class, register dependency
function Service(A, B) { 
    A()
    B()
} 

getFuncParams = function (func) { 
    var matches = func.toString().match(/^function\s*[^\(]*\(\s*([^\)]*)\)/m); 
    if (matches && matches.length > 1) 
        return matches[1].replace(/\s+/, '').split(','); 
    return []; 
}

setFuncParams = function (params) { 
    for (var i in params) { 
        params[i] = services[params[i]]; 
    } 
    return params; 
};
// Injector
function Activitor(func, scope) { 
   return () => {
       func.apply(scope || {}, setFuncParams(getFuncParams(func)));
   } 
} 
// Instantiation
var service = Activitor(Service); 
service();//1 2

module.js

var MODULE_TWO = (function (old) {
	var my = {},
		key;
	
	for (key in old) {
		if (old.hasOwnProperty(key)) {
			my[key] = old[key];
		}
	}
	
	var super_moduleMethod = old.moduleMethod;
	my.moduleMethod = function () {
		// override method on the clone, access to super through super_moduleMethod
	};
	
	return my;
}(MODULE||{}));