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WebAssembly.compileStreaming()

The WebAssembly.compileStreaming() function compiles a WebAssembly.Module directly from a streamed underlying source. This function is useful if it is necessary to a compile a module before it can be instantiated (otherwise, the WebAssembly.instantiateStreaming() function should be used).

Syntax

WebAssembly.compileStreaming(source)

Parameters

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.

Return value

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

Exceptions

  • 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.

Examples

Compile streaming

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.

Specifications

Browser compatibility

Desktop Mobile Server
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet Deno Node.js
compileStreaming
61
16
58
No
47
15
61
61
58
45
15
8.0
1.12
No

See also

© 2005–2022 MDN contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/WebAssembly/compileStreaming