What’s the best/standard way of merging two associative arrays in JavaScript? Does everyone just do it by rolling their own for loop?
with jquery you can call $.extend
var obj1 = {a: 1, b: 2};
var obj2 = {a: 4, c: 110};
var obj3 = $.extend(obj1, obj2);
obj1 == obj3 == {a: 4, b: 2, c: 110} // Pseudo JS
(assoc. arrays are objects in js)
look here: http://api.jquery.com/jQuery.extend/
edit: Like rymo suggested, it's better to do it this way:
obj3 = $.extend({}, obj1, obj2);
obj3 == {a: 4, b: 2, c: 110}
As here obj1 (and obj2) remain unchanged.
edit2: In 2018 the way to do it is via Object.assign:
var obj3 = Object.assign({}, obj1, obj2);
obj3 === {a: 4, b: 2, c: 110} // Pseudo JS
If working with ES6 this can be achieved with the Spread Operator:
const obj3 = { ...obj1, ...obj2 };
