Package Exports

@rollup/plugin-wasm

This package does not declare an exports field, so the exports above have been automatically detected and optimized by JSPM instead. If any package subpath is missing, it is recommended to post an issue to the original package (@rollup/plugin-wasm) to support the "exports" field. If that is not possible, create a JSPM override to customize the exports field for this package.

Readme

@rollup/plugin-wasm

🍣 A Rollup which allows importing and bundling WebAssembly modules.

WebAssembly Modules are imported asynchronous as base64 strings. Small modules can be imported synchronously.

Requirements

This plugin requires an LTS Node version (v8.0.0+) and Rollup v1.20.0+.

Install

Using npm:

npm install @rollup/plugin-wasm --save-dev

Usage

Create a rollup.config.js configuration file and import the plugin:

import { wasm } from '@rollup/plugin-wasm';

export default {
  input: 'src/index.js',
  output: {
    dir: 'output',
    format: 'cjs'
  },
  plugins: [wasm()]
};

Then call rollup either via the CLI or the API.

Options

`sync`

Type: Array[...String]
Default: null

Specifies an array of strings that each represent a WebAssembly file to load synchronously. See Synchronous Modules for a functional example.

`maxFileSize`

Type: Number
Default: 14336 (14kb)

The maximum file size for inline files. If a file exceeds this limit, it will be copied to the destination folder and loaded from a separate file at runtime. If maxFileSize is set to 0 all files will be copied.

Files specified in sync to load synchronously are always inlined, regardless of size.

`publicPath`

Type: String
Default: (empty string)

A string which will be added in front of filenames when they are not inlined but are copied.

WebAssembly Example

Given the following simple C file:

int main() {
  return 42;
}

Compile the file using emscripten, or the online WasmFiddle tool. Then import and instantiate the resulting file:

import sample from './sample.wasm';

sample({ ...imports }).then(({ instance }) => {
  console.log(instance.exports.main());
});

The WebAssembly is inlined as a base64 encoded string. At runtime the string is decoded and a module is returned.

Note: The base64 string that represents the WebAssembly within the bundle will be ~33% larger than the original file.

Synchronous Modules

Small modules (< 4KB) can be compiled synchronously by specifying them in the configuration.

wasm({
  sync: ['web/sample.wasm', 'web/foobar.wasm']
});

This means that the exports can be accessed immediately.

import sample from './sample.wasm';

const instance = sample({ ...imports });

console.log(instance.exports.main());