tsconfig.json

{
  // see https://www.typescriptlang.org/tsconfig to better understand tsconfigs
  "include": ["src"],
  "exclude": [
    "./node_modules",
    "**/*.test.ts",
    "**/*.test.js" // for migration
  ],
  "compilerOptions": {
    "target": "es6",
    "module": "es6",
    "lib": ["DOM", "ES2017"],
    "importHelpers": true,
    // output .d.ts declaration files for consumers
    "declaration": true,
    // output .js.map sourcemap files for consumers
    //"sourceMap": true,
    "resolveJsonModule": true,
    // match output dir to input dir. e.g. dist/index instead of dist/src/index
    "rootDir": "./src",
    "strictNullChecks": false,
    "strictPropertyInitialization": false,
    "suppressImplicitAnyIndexErrors": true,
    "outDir": "dist",
    // stricter type-checking for stronger correctness. Recommended by TS
    "strict": true,
    // linter checks for common issues
    //"noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    // noUnused* overlap with @typescript-eslint/no-unused-vars, can disable if duplicative
    // "noUnusedLocals": true,
    //"noUnusedParameters": false,
    // use Node's module resolution algorithm, instead of the legacy TS one
    "moduleResolution": "node",
    // transpile JSX to React.createElement
    // "jsx": "react",
    // interop between ESM and CJS modules. Recommended by TS
    "esModuleInterop": true,
    // significant perf increase by skipping checking .d.ts files, particularly those in node_modules. Recommended by TS
    "skipLibCheck": true,
    // error out if import and file system have a casing mismatch. Recommended by TS
    "forceConsistentCasingInFileNames": true,
    // `tsdx build` ignores this option, but it is commonly used when type-checking separately with `tsc`
    // "noEmit": true,
    "downlevelIteration": true,
    "incremental": true,
    "tsBuildInfoFile": "./buildcache/",
    "types": ["node", "jest", "cypress", "@percy/cypress"]
  }
}