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
Specification | Status | Comment |
---|---|---|
WebAssembly JavaScript API The definition of 'WebAssembly.Instance objects' in that specification. |
Draft | Initial draft definition. |
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).