monaco-yaml-inline

monaco-yaml-inline is a non‑worker alternative to monaco-yaml. It respects and follows the monaco-yaml API surface and behavior, but runs the YAML language service inline on the main thread instead of using a Web Worker.

This project is intentionally aligned with monaco-yaml’s design and API. If you can use Web Workers, monaco-yaml is still the recommended and more performant choice.

Why this exists

Some environments can’t (or don’t want to) use Web Workers:

• embedded editors (inside native apps or constrained iframes)
• custom bundlers without worker support
• SSR + hydration setups where worker URLs are hard to manage

This project provides the same YAML features while keeping integration simple and universal.

Trade‑offs

Pros

• Works in any Monaco Editor environment without worker setup
• Easy to integrate with custom bundlers or CDN usage

Cons

• No Web Worker → YAML analysis runs on the main thread
• Large YAML files can cause noticeable UI slowdowns

Features

• YAML validation (schema-based)
• Completion
• Hover
• Definitions
• Document formatting
• On-type formatting
• Code actions
• Document symbols, links, folding, selection ranges

Install

npm install monaco-yaml-inline

monaco-editor is a peer dependency. yaml-language-server is bundled internally.

Usage (CDN)

import { init } from "https://esm.sh/modern-monaco";
const { configureMonacoYaml } = await import(
  "https://esm.sh/monaco-yaml-inline?bundle&target=es2020"
);

const monaco = await init();

configureMonacoYaml(monaco, {
  schemas: [
    {
      uri: "inmemory://schema.yaml",
      fileMatch: ["**/*.yaml", "**/*.yml"],
      schema: {
        type: "object",
        properties: {
          name: { type: "string" }
        }
      }
    }
  ]
});

API

configureMonacoYaml(monaco, options)

Registers YAML language features on a Monaco instance. Returns a handle:

• dispose() – removes providers and markers
• update(options) – updates settings and revalidates

Options

• completion, hover, validate, format
• customTags, schemas, enableSchemaRequest
• yamlVersion, isKubernetes
• schemaRequestService

License

MIT