WebAssembly.Instance.prototype.exports

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since October 2017.

The exports readonly property of the WebAssembly.Instance object prototype 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.

Examples

Using exports

After fetching some WebAssembly bytecode using fetch, we compile and instantiate the module using the WebAssembly.instantiateStreaming() function, importing a JavaScript function into the WebAssembly Module in the process. We then call an Exported WebAssembly function that is exported by the Instance.

js
const importObject = {
  my_namespace: {
    imported_func(arg) {
      console.log(arg);
    },
  },
};

WebAssembly.instantiateStreaming(fetch("simple.wasm"), importObject).then(
  (obj) => obj.instance.exports.exported_func(),
);

Note: You can also find this example as instantiate-streaming.html on GitHub (view it live also).

Specifications

Specification
WebAssembly JavaScript Interface
# dom-instance-exports

Browser compatibility

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See also