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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.instantiateStreaming() 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);
    }
  }
};

WebAssembly.instantiateStreaming(fetch('simple.wasm'), importObject)
.then(obj => obj.instance.exports.exported_func());

Note: You can also find this example as instantiate-streaming.html on GitHub (view it live also).

Specifications

Specification Status Comment
WebAssembly JavaScript Interface
The definition of 'WebAssembly.Instance objects' in that specification.
Working Draft Initial draft definition.

Browser compatibilityUpdate compatibility data on GitHub

Desktop
Chrome Edge Firefox Internet Explorer Opera Safari
Basic support 57 16 52
52
Disabled in the Firefox 52 Extended Support Release (ESR).
No 44 11
Mobile
Android webview Chrome for Android Edge Mobile Firefox for Android Opera for Android iOS Safari Samsung Internet
Basic support 57 57 Yes
Disabled
Yes
Disabled
Disabled This feature is behind the Experimental JavaScript Features preference.
52
52
Disabled in the Firefox 52 Extended Support Release (ESR).
? 11 7.0
Server
Node.js
Basic support 8.0.0

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