Setup

Recommended tooling for a Fusion app project, beyond scaffolding it with ffc create app.

Package manager: pnpm

Fusion Framework apps use pnpm. Use it for installs and scripts instead of npm or yarn — it's faster, and workspace-linked packages (workspace:^) only resolve correctly with pnpm.

# Install pnpm if you don't have it
corepack enable
corepack prepare pnpm@latest --activate

# Install dependencies
pnpm install

# Run a script
pnpm dev
pnpm build

If your project is a monorepo with multiple apps/packages, declare them in pnpm-workspace.yaml:

packages:
  - 'apps/*'
  - 'packages/*'

TypeScript

Fusion Framework packages ship strict TypeScript types. Keep strict: true in your tsconfig.json — Fusion's APIs are designed around it, and turning it off will surface any-typed gaps in your own code instead of the framework's.

Linting and formatting

See Linting for setting up Biome and Fusion Lint — both are recommended for any Fusion app.

Testing

Fusion Framework uses Vitest and provides a thin integration for
testing React apps in Vitest Browser Mode. The integration initializes the real application
module scope and deterministic Fusion boundaries; Vitest continues to own the runner,
assertions, hooks, configuration, and general-purpose mocking.

See Testing Fusion apps for choosing a test layer and
Getting started with app tests for the browser configuration,
first passing test, and CI command. Use the official Vitest documentation
for runner features that are not Fusion-specific.

Editor

Install the Fusion TS Lint and Biome VS Code extensions, and set Biome as your default formatter:

// .vscode/settings.json
{
  "editor.defaultFormatter": "biomejs.biome",
  "editor.formatOnSave": true
}