Resizable ArrayBuffer and growable SharedArrayBuffer

Category: JavaScript
Type: Chromium catches up
Status: Enabled by default (Chrome 111)
Intent stage: Dev trials

Summary

Extend the ArrayBuffer constructors to take an additional maximum length that allows in-place growth and shrinking of buffers. Similarly, SharedArrayBuffer is extended to take an additional maximum length that allows in-place growth.

Motivation

Allowing ArrayBuffers and SharedArrayBuffers to resize and grow allow for more efficient use, as currently resizing them requires copying. Additionally, WebAssembly linear memory can already resize, and this brings the same capability to JS.

Standards & signals

Specification: https://tc39.es/proposal-resizablearraybuffer/
Firefox: Positive — Assumed positive because this proposal is Stage 3 in TC39.
Safari: Positive — Assumed positive because this proposal is Stage 3 in TC39.
Web developers: No signals
Tracking bug: https://bugs.chromium.org/p/v8/issues/detail?id=11111

Explainers: https://github.com/tc39/proposal-resizablearraybuffer/blob/master/README.md

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