Wasm 2.0 (amber:wasm)

v1.16.0 adds a Preview amber:wasm module so JavaScript and WebAssembly can share the same backing store instead of copying buffers at the boundary.

This is not a new Wasm engine. V8 still compiles and runs Wasm. Amber adds host helpers around WebAssembly.Memory / ArrayBuffer.

What you get

• WebAssembly.Memory.buffer can share pages with a V8 ArrayBuffer via new_backing_store_from_ptr
• mmap-backed module load (large .wasm files are mapped, not fully copied into the isolate first)
• require('amber:wasm') / import wasm from 'amber:wasm'

import wasm from "amber:wasm";

const mem = new WebAssembly.Memory({ initial: 2 });
const addr = wasm.ptr(mem); // bigint host address of linear memory

Standard Wasm still works:

const { instance } = await WebAssembly.instantiate(bytes, imports);
instance.exports.add(1, 2);

Streaming APIs (WebAssembly.compileStreaming / instantiateStreaming) consume Response without stuffing the body through a string.

Status

FFI pointer wrapping and amber:ai.Tensor views exist on the same module; treat those helpers as Preview too.