The WebAssembly.Instance()
constructor creates a new Instance
object which is a stateful, executable instance of a WebAssembly.Module
.
The WebAssembly.Instance()
constructor creates a new Instance
object which is a stateful, executable instance of a WebAssembly.Module
.
Warning: Since instantiation for large modules can be expensive, developers should only use the Instance()
constructor when synchronous instantiation is absolutely required; the asynchronous WebAssembly.instantiateStreaming()
method should be used at all other times.
new WebAssembly.Instance(module, importObject)
module
The WebAssembly.Module
object to be instantiated.
importObject
Optional
An object containing the values to be imported into the newly-created Instance
, such as functions or WebAssembly.Memory
objects. There must be one matching property for each declared import of module
or else a WebAssembly.LinkError
is thrown.
TypeError
is thrown. WebAssembly.CompileError
, WebAssembly.LinkError
, or WebAssembly.RuntimeError
are thrown, depending on the cause of the failure. RangeError
, as they prohibit compilation and instantiation of Wasm with large buffers on the UI thread. The WebAssembly.Instance()
constructor function can be called to synchronously instantiate a given WebAssembly.Module
object, for example:
const importObject = { imports: { imported_func(arg) { console.log(arg); } } }; fetch('simple.wasm').then((response) => response.arrayBuffer() ).then((bytes) => { const mod = new WebAssembly.Module(bytes); const instance = new WebAssembly.Instance(mod, importObject); instance.exports.exported_func(); })
However, the preferred way to get an Instance
is through the asynchronous WebAssembly.instantiateStreaming()
function, for example like this:
const importObject = { imports: { imported_func(arg) { console.log(arg); } } }; WebAssembly.instantiateStreaming(fetch('simple.wasm'), importObject) .then((obj) => obj.instance.exports.exported_func());
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 | |
Instance |
57 |
16 |
52 |
No |
44 |
11 |
57 |
57 |
52 |
43 |
11 |
7.0 |
1.0 |
8.0.0 |
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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/Instance