MoonBit JS Binding Guide

Step-by-step workflow for binding JavaScript APIs (browser DOM, Node built-ins, npm packages) to MoonBit through the js backend.

When To Use

Use this skill when:

Adding extern "js" fn declarations for a JS API
Embedding inline JS (#| (x) => ...) or importing by module+name (= "Math" "max")
Configuring moon.pkg with link.js exports and format: esm/cjs/iife
Wrapping JS objects with #external pub type and %identity casts
Bridging Promises with async fn + %async.suspend + %async.run
Mapping undefined / null distinctly into MoonBit Option
Consuming npm packages via require(...) or ESM imports
Generating .d.ts for TypeScript consumers