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WebAssembly.module

A WebAssembly.Module object contains stateless WebAssembly code that has already been compiled by the browser and can be efficiently shared with Workers, and instantiated multiple times. To instantiate the module, call the secondary overload of WebAssembly.instantiate(). The WebAssembly.Module() constructor function can be called to synchronously compile given WebAssembly binary code. However, the primary way to get a Module is through an asynchronous compilation function like WebAssembly.compile().

Constructor Syntax

Important: Since compilation for large modules can be expensive, developers should only use the Module() constructor when synchronous compilation is absolutely required; the asynchronous WebAssembly.compileStreaming() method should be used at all other times.

var myModule = new WebAssembly.Module(bufferSource);

Parameters

bufferSource: A typed array or ArrayBuffer containing the binary code of the .wasm module you want to compile.

Function Properties of the `Module` Constructor

WebAssembly.Module.customSections(): Given a Module and string, returns a copy of the contents of all custom sections in the module with the given string name.
WebAssembly.Module.exports(): Given a Module, returns an array containing descriptions of all the declared exports.
WebAssembly.Module.imports(): Given a Module, returns an array containing descriptions of all the declared imports.

`Module` instances

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

Instance properties

Module.prototype.constructor: Returns the function that created this object's instance. By default this is the WebAssembly.Module() constructor.
Module.prototype[@@toStringTag]: The initial value of the @@toStringTag property is the String value "WebAssembly.Module".

Instance methods

Module instances have no default methods of their own.

Specifications

Specification	Status	Comment
WebAssembly JavaScript Interface The definition of 'WebAssembly.Module()' 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
`customSections`	57	16	52 52 Disabled in the Firefox 52 Extended Support Release (ESR).	No	44	11
`exports`	57	16	52 52 Disabled in the Firefox 52 Extended Support Release (ESR).	No	44	11
`imports`	57	16	52 52 Disabled in the Firefox 52 Extended Support Release (ESR).	No	44	11
`prototype`	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
`customSections`	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
`exports`	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
`imports`	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
`prototype`	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
`customSections`	8.0.0
`exports`	8.0.0
`imports`	8.0.0
`prototype`	8.0.0