Integers in JavaScript

Question

I'm a beginner to Javascript so forgive me if I sound dumb because I learned some Javascript from W3Fools (which are really difficult tutorials - they don't explain anything I want to know, but everything I probably can guess from my experience with C++).

I may be switching over to MDN, but if you can recommend any other tutorials, that be great.

Anyways, so here's my question:

I just read a few lines of this, and apparently:

Numbers in JavaScript are "double-precision 64-bit format IEEE 754 values", according to the spec. This has some interesting consequences. There's no such thing as an integer in JavaScript, so you have to be a little careful with your arithmetic if you're used to math in C or Java.

I've already seen that there are few of the data types (for variables) I'm used to from C++. But I didn't expect all numbers to automatically be floats. Isn't there any way to use integers, not float? Will a future version of JavaScript support ints?

Answer 1

There are really only a few data types in Javascript: Objects, numbers, and strings. As you read, JS numbers are all 64-bit floats. There are no ints.

Firefox 4 will have support for Typed Arrays, where you can have arrays of real ints and such: https://developer.mozilla.org/en/JavaScript_typed_arrays

Until then, there are hackish ways to store integer arrays as strings, and plucking out each integers using charCodeAt().

Answer 2

I don't think it ever will support integers. It isn't a problem as every unsigned 32 bit integer can be accurately represented as a 64 bit floating point number.

Modern JavaScript engines could be smart enough to generate special code when the numbers are integer (with safeguard checks to make sure of it), but I'm not sure.