一些JavaScript代码的优化

Question

the follwoing code

$.concat||$.extend({concat:function(b,c){var a=[];for(x in arguments)a=a.concat(arguments[x]);return a}}); 

$(document).ready(function(){

    //document ready

    var solobroadcast_template =$("#hidden_solobroadcast").html()
    var b = new Array();   
    b.push([{"indexname": "green", "url":"#Green"}])
    b.push([{"indexname": "red", "url":"#red"}])    
   //....... more elements come here 

   //how can we know b[] while the array b contain unknown keys
   var bindexes = $.concat(b[0],b[1]);   



    var convertedvars = {
        name: "sam",
        indexes: function (){return bindexes}

    }


    var output = Mustache.render(solobroadcast_template, convertedvars);
    document.getElementById("content").innerHTML = output;
});

as it runs on http://jsfiddle.net/mshannaq/ZqqMe/6/

as you can see the variable bindexes = $.concat(b[0],b[1]); and in this case its static for b[0] and b[1] but what shloud we do if we want to to cocat all the b array size . imagin that b array size may be 1000 element and its dynamic.

Answer 1

Just add objects to the array instead adding the array:

b.push({"indexname": "green", "url":"#Green"})
b.push({"indexname": "red", "url":"#red"})

var convertedvars = {
    name: "sam",
    indexes: function (){return b;}
}

Then you already have an array of what you need, instead of concatenating all your smaller arrays.

Demo: http://jsfiddle.net/ZqqMe/11/

Answer 2

in this case to fix this we use

 var bindexes = [];
 bindexes = bindexes.concat.apply(bindexes, b);

insted of using

var bindexes = $.concat(b[0],b[1]);

and now what ever how much b array elements they will be mereged

http://jsfiddle.net/mshannaq/ZqqMe/8/

as says on Merge/flatten an array of arrays in JavaScript?