tsconfig.json

{
    "compilerOptions": {
        "lib": ["es5", "es6"],
        "outDir": "./dist",
        "allowSyntheticDefaultImports": true,
        "esModuleInterop": true,
        "target": "es5",
        "module": "commonjs",
        "moduleResolution": "node",
        "emitDecoratorMetadata": true,
        "experimentalDecorators": true,
        "sourceMap": true,
        "noImplicitAny": true,
        "noFallthroughCasesInSwitch": true,
        "noImplicitReturns": true,
        "stripInternal": true,
        "pretty": true,
        "strictNullChecks": true,
        "noUnusedLocals": true,
        "downlevelIteration": true,
        "rootDir": ".",
        // Ensure that .d.ts files are created by tsc, but not .js files
        "declaration": true,
        "declarationMap": true,
        "resolveJsonModule": true
    },
    "include": ["lib/**/*"],
    "exclude": ["node_modules"]
}