This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.
The WebAssembly.exports()
function returns an array containing descriptions of all the declared exports of the given Module
.
Syntax
var exports = 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
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.compile()
function and then sends it to a worker using postMessage().
var worker = new Worker("wasm_worker.js"); fetch('simple.wasm').then(response => response.arrayBuffer() ).then(bytes => WebAssembly.compile(bytes) ).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
Specification | Status | Comment |
---|---|---|
Web Assembly JavaScript API The definition of 'exports()' in that specification. |
Draft | Initial draft definition. |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|---|
Basic support | 57 | 15[2] | 52 (52)[1] | No support | 44 | 11 |
Feature | Chrome for Android | Android Webview | Edge Mobile | Firefox Mobile (Gecko) | IE Mobile | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|
Basic support | 57 | 57 | No support | 52.0 (52)[1] | No support | No support | 11 |
[1] WebAssembly is enabled in Firefox 52+, although disabled in the Firefox 52 Extended Support Release (ESR.)
[2] Currently supported behind the “Experimental JavaScript Features” flag. See this blog post for more details.