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WebAssembly.instance.exports

The exports readonly property of the WebAssembly.Instance object prototype returns an object containing as its members all the functions exported from the WebAssembly module instance, to allow them to be accessed and used by JavaScript.

instance.exports

Examples

After fetching some WebAssembly bytecode using fetch, we compile and instantiate the module using the WebAssembly.instantiate() function, importing a JavaScript function into the WebAssembly Module in the process. We then call an Exported WebAssembly function that is exported by the Instance.

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

fetch('simple.wasm').then(response =>
  response.arrayBuffer()
).then(bytes =>
  WebAssembly.instantiate(bytes, importObject)
).then(result =>
  result.instance.exports.exported_func()
);

Note: See index.html on GitHub (view it live also) for a similar example that makes use of our fetchAndInstantiate() library function.

Specifications

Browser compatibility

Feature Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 57 16 522 No 44 11
Feature Android webview Chrome for Android Edge mobile Firefox for Android IE mobile Opera Android iOS Safari
Basic support 57 57 Yes1 522 No ? 11

1. This feature is behind the Experimental JavaScript Features preference.

2. Disabled in the Firefox 52 Extended Support Release (ESR).

See also

© 2005–2018 Mozilla Developer Network and individual 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/Instance/exports