Clarification: Maximum size of an array

[nzakas]

Something I noticed while reading through the spec: it appears that the maximum size of an array can now be 2^53-1 based on ToLength, which is used in several places (for example, Array.prototype.concat).

However, it looks like the Array constructor still limits the length to 2^32-1.

I'm curious if this difference is intentional?

[nzakas]

(I'm guessing this is some back compat issue, just wanted to double-check.)

[nzakas]

(I'm guessing this is some back compat issue, just wanted to double-check.)

[allenwb]

Yes, it's intentional. The Array.prototype methods were generally re-specified to work with collections up to ToLength size (for example, TypedArrays can in theory be that big). But for back compact reasons Array instances are restricted to a length of 2^32-1 with Uint32 index warping.

[allenwb]

Yes, it's intentional. The Array.prototype methods were generally re-specified to work with collections up to ToLength size (for example, TypedArrays can in theory be that big). But for back compact reasons Array instances are restricted to a length of 2^32-1 with Uint32 index warping.

[nzakas]

Cool, thanks!

[nzakas]

Cool, thanks!