source

A Response object or a promise that will fulfill with one, representing the underlying source of a .wasm module you want to stream and compile.

A Promise that resolves to a WebAssembly.Module object representing the compiled module.

• If source is not a Response or Promise resolving to a Response, the promise rejects with a TypeError.
• If compilation fails, the promise rejects with a WebAssembly.CompileError.
• If the source is a Promise that rejects, the promise rejects with the error.
• If the source Result has an error (e.g. bad MIME type), the promise rejects an error.

The following example (see our compile-streaming.html demo on GitHub, and view it live also) directly streams a .wasm module from an underlying source then compiles it to a WebAssembly.Module object. Because the compileStreaming() function accepts a promise for a Response object, you can directly pass it a fetch() call, and it will pass the response into the function when it fulfills.

const importObject = { imports: { imported_func: (arg) => console.log(arg) } };

WebAssembly.compileStreaming(fetch('simple.wasm'))
  .then((module) => WebAssembly.instantiate(module, importObject))
  .then((instance) => instance.exports.exported_func());

The resulting module instance is then instantiated using WebAssembly.instantiate(), and the exported function invoked.

• WebAssembly overview page
• WebAssembly concepts
• Using the WebAssembly JavaScript API