demo · v133

Wasm Memory64

Construct a real 64-bit-indexed WebAssembly.Memory from JS, then bump it past the old 32-bit-indexed ceiling and read its buffer back. Browsers without memory64 reject the constructor option.

buffer.byteLength
-
addressing
-

checking support...

the code

// Memory64 enabled: pass index: "i64".
const mem = new WebAssembly.Memory({
  initial: 2,
  maximum: 65536,
  index: "i64",            // NEW in Chrome 133 - opt-in to 64-bit addressing
});
mem.grow(4);
console.log(mem.buffer.byteLength); // can exceed 4GB

see also