Appending to an object - javascript

Question

If I do the following,

var array = [];
array['foo'] = [];
console.log(array.length)   // => 0

the console.log prints 0 length.

Is there a way to push key-value to arrays in javascript? Is it a bad idea in general? Do I need to keep the length updated myself?

There is the option to use bracket notation as recommended here ( SO - JavaScript Array Push key value ).

But later in the code I want to push to the object/array and SO recommends to use arrays again ( SO - Appending to an object ).

So I'm not quite sure which datastructure to use. For my task I guess I need key-values. Its an async-task and I can't rely on the order in an unnamed array. But from what I read so far, it seems kind of a hack to append to objects, too.

Answer 1

You can push an object:

var arr = [];
var obj = {foo: "bar"};
arr.push(obj);
arr.length; //1
arr[0].foo; //"bar"

Answer 2

You should probably use a javascript object , which acts as a key/value pair data structure (like a HashMap or a Dictionary ).

var data = {
  key: 'value'
}

data['key'] // 'value'
Object.keys(data).length // 1

For the sake of your future self, you should not add properties to an array nor try to simulate an array with an object.