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WebAssembly.Module.exports()

The WebAssembly.Module.exports() function returns an array containing descriptions of all the declared exports of the given Module.

Syntax

WebAssembly.Module.exports(module)

Parameters

module

A WebAssembly.Module object.

Return value

An array containing objects representing the exported functions of the given module.

Exceptions

If module is not a WebAssembly.Module object instance, a TypeError is thrown.

Examples

Using exports

The following example (see our index-compile.html demo on GitHub, and view it live also) compiles the loaded simple.wasm byte code using the WebAssembly.compileStreaming() method and then sends it to a worker using postMessage().

var worker = new Worker("wasm_worker.js");

WebAssembly.compileStreaming(fetch('simple.wasm'))
.then(mod =>
  worker.postMessage(mod)
);

In the worker (see wasm_worker.js) we define an import object for the module to use, then set up an event handler to receive the module from the main thread. when the module is received, we create an instance from it using the WebAssembly.Instantiate() method, invoke an exported function from inside it, then show how we can return information on the available exports on a module using WebAssembly.Module.exports.

var importObject = {
  imports: {
    imported_func: function(arg) {
      console.log(arg);
    }
  }
};

onmessage = function(e) {
  console.log('module received from main thread');
  var mod = e.data;

  WebAssembly.instantiate(mod, importObject).then(function(instance) {
    instance.exports.exported_func();
  });

  var exports = WebAssembly.Module.exports(mod);
  console.log(exports[0]);
};

The exports[0] output looks like this:

{ name: "exported_func", kind: "function" }

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
exports
57
16
52
Disabled in the Firefox 52 Extended Support Release (ESR).
No
44
11
57
57
52
Disabled in the Firefox 52 Extended Support Release (ESR).
43
11
7.0
1.0
8.0.0

See also

© 2005–2021 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/Module/exports