WebAssembly.Instance

A WebAssembly.Instance object is a stateful, executable instance of a WebAssembly.Module.  Instance objects contain all the Exported WebAssembly functions that allow calling into WebAssembly code from JavaScript.

The WebAssembly.Instance() constructor function can be called to synchronously instantiate a given WebAssembly.Module object. However, the primary way to get an Instance is through the asynchronous WebAssembly.instantiateStreaming() function.

Constructor Syntax

var myInstance = new WebAssembly.Instance(module, importObject);

Parameters

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.

Instance instances

All Instance instances inherit from the Instance() constructor's prototype object — this can be modified to affect all Instance instances.

Instance properties

Instance.prototype.constructor

Returns the function that created this object's instance. By default this is the WebAssembly.Instance() constructor.

Instance.prototype.exports Read only

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 methods

None.

Specifications

Browser compatibility

See also

• WebAssembly overview page
• WebAssembly concepts
• Using the WebAssembly JavaScript API