WebAssembly.compile

The compile() method of the WebAssembly object compiles a .wasm file loaded into the JavaScript context as a typed array (e.g. using Fetch/arrayBuffer into a Module object instance.

Syntax

WebAssembly.compile(bufferSource).then(function(module) {
  // do something with compiled module
});

Parameters

bufferSource

A typed array containing the byte code of the .wasm module you want to compile.

Return value

A promise that resolves to a Module instance representing the compiled module.

Exceptions

• If bufferSource is not a typed array, a TypeError is thrown.
• If compilation fails, the promise rejects with a WebAssembly.CompileError.

Examples

The following example (see our index-compile.html test file on GitHub, and view it live also) compiles the loaded simple.wasm byte code using the compile() method, and then creates an instance using the WebAssembly.Instance() constructor.

It then imports a JavaScript function into the WebAssembly Module in the process, and then exports a function from the module via Instance.exports.

var importObject = {
  imports: {
    imported_func: function(arg) {
      console.log(arg);
    }
  }
};

fetch('simple.wasm').then(function(response) {
  response.arrayBuffer().then(function(bytes) {
    WebAssembly.compile(bytes).then(function(mod) {
      var instance = new WebAssembly.Instance(mod, importObject);
      instance.exports.exported_func();
    })
  })
});

Specifications

Specification	Status	Comment
Unknown The definition of 'compile()' in that specification.	Unknown	Initial draft definition.

Browser compatibility

[1] Experimental support can be enabled in Chrome 51+ and Opera 38+ by going to chrome://flags and enabling the Experimental WebAssembly flag.

[2] Experimental support can be enabled in Firefox 47+ by enabling the javascript.options.wasm flag in about:config.

See also

• WebAssembly landing page.
• WebAssembly concepts
• Using the WebAssembly JavaScript API