tsconfig.json

{
    "compilerOptions": {
        "target": "es2016" /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017', or 'ESNEXT'. */,
        "module": "commonjs" /* Specify module code generation: 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */,
        "lib": ["es2017", "dom"] /* Specify library files to be included in the compilation:  */,
        "declaration": true /* Generates corresponding '.d.ts' file. */,
        "sourceMap": true /* Generates corresponding '.map' file. */,
        "outDir": "./dist" /* Redirect output structure to the directory. */,
        /* Strict Type-Checking Options */
        "strict": true /* Enable all strict type-checking options. */,
        "noImplicitAny": true /* Raise error on expressions and declarations with an implied 'any' type. */,
        "strictNullChecks": true /* Enable strict null checks. */,
        /* Additional Checks */
        "noUnusedLocals": true /* Report errors on unused locals. */,
        "noUnusedParameters": true /* Report errors on unused parameters. */,
        "noImplicitReturns": true /* Report error when not all code paths in function return a value. */,
        "noFallthroughCasesInSwitch": true /* Report errors for fallthrough cases in switch statement. */,
        /* Module Resolution Options */
        // "typeRoots": []                        /* List of folders to include type definitions from. */
        "moduleResolution": "node" /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */,
        "resolveJsonModule": true /* Allow json modules to be imported and enable json type checking */,
        "forceConsistentCasingInFileNames": true
    },
    "include": ["./src/**/*.ts", "./tests/**/*.ts"]
}