moon v1.17 - Full Bun support, TypeScript improvements, and more!

In this release, we've focused heavily on the JavaScript and TypeScript ecosystems, by improving our implementations, and providing full Bun support.

Bun tier 1, 2, and 3 support

Yes you read that right! Not just 1 tier, not just 2 tiers, but all 3 language tiers have been implemented for Bun, providing full language support, and parity with Node.js. Thanks to the Bun work in proto and the previous v1.16 release, we were able to add full Bun support with relative easy.

So what does Bun support look like? To start, you can now configure a bun setting in .moon/toolchain.yml, including an optional version to download and install, and settings similar to Node.js.

.moon/toolchain.yml

bun:
  version: '1.0.13'
  syncProjectWorkspaceDependencies: true

This will enable the bun platform and the following integrations are applied:

• Will automatically download and install Bun for the configured version.
• Will install dependencies using bun install (deduping currently not supported).
• Will parse bun.lockb for dependency resolution and task hashing.
• Will use bunx instead of npx for one-off package executions.
• Can execute bun commands within tasks.

With the bun platform enabled, you can now configure the platform for projects and tasks (is automatically detected when running the bun or bunx commands).

<project>/moon.yml

# Default platform for all tasks (optional)
platform: 'bun'

tasks:
  dev:
    command: 'bun run dev'
  test:
    command: 'bun test'
  lint:
    command: 'eslint .'
    # Only required for npm packages (if not defined above)
    platform: 'bun'

TypeScript improvements

Configure the root directory

When moon was first designed, it was designed for JavaScript based monorepos. Because of this, there were a handful of assumptions that still exist today, one of which is that the moon workspace root was assumed to be the JavaScript and TypeScript root. The root is extremely important in resolving relative paths for project references and other path based functionality, so using the workspace root made the most sense.

However, what if your TypeScript root isn't the workspace root? Or the TypeScript root and JavaScript root are different? Well, you were out of luck... until now! We're introducing a new setting called typescript.root, that denotes the root directory for TypeScript related functionality (relative from moon's workspace root).

.moon/toolchain.yml

typescript:
  root: './typescript'

Include shared types

Another common TypeScript practice is to have shared .d.ts types that are used across multiple projects, or to augment third-party types. This is so common that we felt obligated to support it in some capacity within moon. With that said, we're introducing a new setting, typescript.includeSharedTypes.

.moon/toolchain.yml

typescript:
  includeSharedTypes: true

When enabled, we'll automatically sync the shared types path to the include field of all relevant project tsconfig.jsons. However, for this to work correctly, the shared types must exist in a types folder relative from the TypeScript root.

For example, if the TypeScript root is /, and shared types is /types, then all packages in /packages/* will be updated with the following:

packages/example/tsconfig.json

{
  "include": ["../../types/**/*"]
}

This setting can be overridden on a per-project basis.

Include sources of project references

Continuing with include related functionality, we've introducing yet another new setting, typescript.includeProjectReferenceSources, which does exactly as its name implies. It automatically appends the sources (**/*) of all project references to the include field of all relevant project tsconfig.jsons.

This is useful (and sometimes required) for the following reasons:

• It makes files within a referenced project available for import into the consuming project. This is required for "press tab to auto-import" nested/deep files, otherwise only index imports will work (and barrel files are costly).
• It also improves the editor experience by making the source files available for intellisense, autocomplete, and other features.

.moon/toolchain.yml

typescript:
  includeProjectReferenceSources: true

To understand this functionality, say you have a project with the following tsconfig.json, and this project depends on 2 other projects: ui and utils.

packages/example/tsconfig.json

{
  "compilerOptions": {},
  "include": ["src/**/*"]
}

When our syncing process occurs, we'll automatically sync project references, and include referenced sources, like so.

packages/example/tsconfig.json

{
  "compilerOptions": {},
  "include": ["src/**/*", "../ui/**/*", "../utils/**/*"],
  "references": [{ "path": "../ui" }, { "path": "../utils" }]
}

This setting can also be overridden on a per-project basis.

JavaScript improvements

Supporting the "single version policy" pattern

If you're unfamiliar with the single version policy, or the one version rule, it's a pattern that only allows dependencies to be configured in a single location, typically the root package.json. This pattern forces all projects in a monorepo to use the same dependencies, and avoid the package workspaces functionality.

This pattern was previously not possible in moon, as our automatic dependency installation process did not account for it, and it would either install in the root if using workspaces, or in a project otherwise. To support this pattern, we're introducing the new setting node.rootPackageOnly for Node.js, and bun.rootPackageOnly for Bun.

.moon/toolchain.yml

node:
  rootPackageOnly: true

When enabled, we'll only install dependencies in the workspace root, regardless of other settings or how package.jsons are configured. However, this setting does not verify that other package.jsons do not have dependencies. It's up to you to ensure that other package.jsons do not have dependencies.

Other changes

View the official release for a full list of changes.

• Updated automatic dependency linking to use the build scope instead of peer scope. This should alleviate some of the pain points with package.json syncing.
• Improved project reference syncing and edge case handling.