SharedArrayBuffer

• SharedArrayBuffer - JavaScript

SharedArrayBuffer is an object that holds a fixed-length binary buffer. You can pass around comparably longer data with SharedArrayBuffer between agents (i.e., main thread and worker.) A change in one ShardArrayBuffer will reflect on the other side.

const sab = new SharedArrayBuffer(1024)
worker.postMessage(sab)

The Spectre vulnerability seized ShardArrayBuffer in 2018, and since 2020, ShardArrayBuffer requires a Secure Context to run.

For the host document, I need two headers to enable ShardArrayBuffer.

• Cross-Origin-Opener-Policy with same-origin as value (protects your origin from attackers)
• Cross-Origin-Embedder-Policy with require-corp as value (protects victims from your origin)