tsconfig.json

{
  // TypeScript configuration for this Office Scripts project and its tests.
  //
  // - "strictNullChecks" is set to false because Office Scripts APIs often return 'undefined'
  //   where TypeScript expects 'null'. Enabling strict null checks would cause excessive
  //   type errors or require verbose code, which is impractical for this context.
  //
  // - "mocks" and "wrappers" directories are included to support local unit testing and
  //   development outside Excel Online.
  //
  // - "typeRoots" includes both custom Office Scripts typings and standard @types packages.
  //   This ensures IntelliSense and type checking works for both Office Scripts mocks and
  //   any Node.js or test framework typings.
  //
  // - All strict type checks except strictNullChecks are enabled for code quality.
  // - "include" covers all source, test, mock, and type definition files.
  // - "exclude" omits build and dependency artifacts.
  "compilerOptions": {
    "target": "es2019",               // Output ES2019-compatible JS (irrelevant for Office Scripts, but required for Node)
    "module": "commonjs",             // Module system for Node.js compatibility
    "declaration": true,              // Generate .d.ts type declaration files
    "outDir": "dist",                 // Output directory for build artifacts
    "rootDir": ".",                   // Project root as rootDir to capture all code
    "strict": true,                   // Enable all strict type-checking options
    "strictNullChecks": false,        // Disable strict null/undefined checks (see note above)
    "esModuleInterop": true,          // Enable ES module/CommonJS import compatibility
    "typeRoots": [
      "./types",                      // Custom Office Scripts and project type definitions
      "./node_modules/@types"         // Standard type definitions from npm packages
    ]
  },
  "include": [
    "src/**/*",
    "test/**/*",
    "types/**/*.d.ts",
    "wrappers/**/*.ts",
    "mocks/**/*.ts"
  ],
  "exclude": [
    "dist",
    "node_modules"
  ]
}