Question

I’m relatively new to Javascript, and there’s probably just a trick I’m not familiar with, but how can I assign boolean values to Array keys?

What’s happening:

var test = new Array();
test[false] = "asdf";
test['false'] = "fdsa";

Object.keys(test); // Yield [ "false" ]
Object.keys(test).length; // Yield 1

What I want to happen:

var test = new Array();

//Some stuff

Object.keys(test); // Yield [ "false" , false ]
Object.keys(test).length; // Yield 2

Answer 1

You can’t use arbitrary indexes in an array, but you can use an object literal to (sort of) accomplish what you’re after:

var test = {};
test[false] = "asdf";
test['false'] = "fdsa";

However it should be noted that object properties must be strings (or types that can be converted to strings). Using a boolean primitive will just end up in creating an object property named 'false'.

test[false] === test['false'] === test.false

This is why your first example’s Object.keys().length call returns just 1.

For an excellent getting started guide on objects in JavaScript, I would recommend MDN’s Working with objects.