TypeScript

To install the TypeScript definitions for Bun's built-in APIs, install @types/bun.

terminal

$ bun add -d @types/bun  # dev dependency

At this point, you should be able to reference the Bun global in your TypeScript files without seeing errors in your editor.

Suggested `compilerOptions`

Bun supports things like top-level await, JSX, and extensioned .ts imports, which TypeScript doesn't allow by default. Below is a set of recommended compilerOptions for a Bun project, so you can use these features without seeing compiler warnings from TypeScript.

tsconfig.json

{
  "compilerOptions": {
    // Environment setup & latest features
    "lib": ["ESNext"],
    "target": "ESNext",
    "module": "Preserve",
    "moduleDetection": "force",
    "jsx": "react-jsx",
    "allowJs": true,

    // Bundler mode
    "moduleResolution": "bundler",
    "allowImportingTsExtensions": true,
    "verbatimModuleSyntax": true,
    "noEmit": true,

    // Best practices
    "strict": true,
    "skipLibCheck": true,
    "noFallthroughCasesInSwitch": true,
    "noUncheckedIndexedAccess": true,
    "noImplicitOverride": true,

    // Some stricter flags (disabled by default)
    "noUnusedLocals": false,
    "noUnusedParameters": false,
    "noPropertyAccessFromIndexSignature": false
  }
}

If you run bun init in a new directory, this tsconfig.json will be generated for you. (The stricter flags are disabled by default.)

terminal

$ bun init

Suggested compilerOptions

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Suggested `compilerOptions`