rollup-plugin-assemblyscript

2.0.0 verified Mon Apr 27 auth: no javascript

A Rollup plugin (v2.0.0) that imports AssemblyScript (.as) files and compiles them on-the-fly into WebAssembly modules. It supports custom compiler options, a configurable import matcher (default `asc:` prefix), and optional integration with as-bind for high-level type bindings. Distinct from other WASM plugins by targeting AssemblyScript specifically and offering tight rollup integration. Requires AssemblyScript and as-bind as peer dependencies. Maintained by the AssemblyScript team.

Common errors

error Error: Cannot find module 'rollup-plugin-assemblyscript' ↓

cause Package not installed or CJS require used in ESM-only version.

fix

Run: npm install rollup-plugin-assemblyscript Use: import { asc } from 'rollup-plugin-assemblyscript'

error [!] Error: The requested module 'rollup-plugin-assemblyscript' does not provide an export named 'asc' ↓

cause Importing v1 style (named export 'asc' not available in older versions).

fix

If using v1: import asc from 'rollup-plugin-assemblyscript' If using v2: import { asc } from 'rollup-plugin-assemblyscript'

error TypeError: asc is not a function ↓

cause Wrong import or plugin not called.

fix

Correct usage: plugins: [asc()] (call the function), not plugins: [asc]

Warnings

breaking v2.0.0 migrated to ESM-only; CJS require() will fail. ↓

fix Use ESM imports or dynamic import('rollup-plugin-assemblyscript').

deprecated Import specifier `assemblyscript:` prefix deprecated in v2; use `asc:` instead. ↓

fix Change imports from `assemblyscript:./file.as` to `asc:./file.as`.

broken Missing peer dependencies (assemblyscript or as-bind) cause runtime errors. ↓

fix npm install assemblyscript as-bind

gotcha The plugin compiles files matching the matcher into WASM URLs; imported value is a string URL, not a module instance. ↓

fix Use the URL with WebAssembly.instantiateStreaming or fetch.

gotcha If `useAsBind: true`, as-bind library must be installed and import runtime requires `--exportRuntime` flag (automatically set by plugin). ↓

fix Ensure as-bind is installed and use `import * as wasm from 'asc:./file.as'` to get bindings.

Install

npm install rollup-plugin-assemblyscript

yarn add rollup-plugin-assemblyscript

pnpm add rollup-plugin-assemblyscript

Imports

asc
```
import { asc } from 'rollup-plugin-assemblyscript'
```
Default and named exports are merged; both `asc` and `default` work. v2.0.0 uses ESM.
Plugin (via default import)
wrong
```
const ascPlugin = require('rollup-plugin-assemblyscript')
```
correct
```
import ascPlugin from 'rollup-plugin-assemblyscript'
```
Package is ESM-only in v2; CJS require will throw. Use dynamic import or transpiler.
Import specifier `asc:`
wrong
```
import wasm from './addition.as'
```
correct
```
import wasmUrl from 'asc:./addition.as'
```
Imports must use the `asc:` prefix (default matcher) to trigger compilation. Without prefix, Rollup treats it as a regular file.

Quickstart

Shows minimal rollup config using asc plugin with compiler options, default matcher, and as-bind disabled.

// rollup.config.js
import { asc } from 'rollup-plugin-assemblyscript';
import { defineConfig } from 'rollup';

export default defineConfig({
  input: 'src/main.js',
  output: { dir: 'dist', format: 'esm' },
  plugins: [
    asc({
      compilerOptions: { optimizeLevel: 3 },
      matcher: /^asc:/,
      useAsBind: false
    })
  ]
});