tsconfig.json

{
  "compilerOptions": {
    "target": "ES2015",
    "allowJs": true,
    "checkJs": false,
    /*
    `noEmit` by default to prevent accidentally emitting in leaf projects i.e. clients and apps.
    Internal projects must override this setting to emit declarations. The compilerOptions they
    must add are:

    ```
      "composite": true,  // Allows them to be `references` in other projects
      "noEmit": false,  // Allows them to emit declarations
      "emitDeclarationOnly": true,  // Prevent them from emitting JS
      "declarationDir": "types"  // Emit the declarations into a separate directory that we can
      gitignore
    ```

    Additionally they must declare their `includes`. See
    https://www.typescriptlang.org/docs/handbook/project-references.html#composite for details.

    The leaf projects then declar `references` to the internal projects they depend on like:

    ```
    "references": [{"path": "../howdju-common"}]
    ```

    This avoids typechecking the internal projects twice. Specifically, it prevents an error where
    the leaf project does not recognize the `@` path for project-relative imports for the
    internal projects.
    */
    "noEmit": true,
    "strict": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true,
    "noImplicitThis": true,
    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "moduleResolution": "node",
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "skipLibCheck": true, // Prevents internal @types/node conflicts like in #60
    "resolveJsonModule": true
  },
  "exclude": ["node_modules", "**/node_modules", "**/dist"]
}