Function 'concat' (in JavaScript) is not working for associative arrays

arrays, concatenation, javascript

Solution

You are not using `Array` functionality - just `Object` functionality. In JavaScript, `Object` is an associative array - you use `Array` for arrays indexed by integers. If you did

var firstArray =  new Array();
firstArray.push("sam");  
firstArray.push("kam");
var secArray =  new Array();
secArray.push("sam");    
secArray.push("kam");
var res = firstArray.concat(secArray);

then `concat` would work as expected.

If you actually want to merge associative arrays, do:

for (var attr in src_array) { dest_array[attr] = src_array[attr]; }

This will of course overwrite existing keys in `dest_array` which have counterparts in `src_array`.

Problem

Original source