tsconfig.json

{
  "compilerOptions": {
    "target": "es6",
    "module": "commonjs",
    "declaration": true /* Generates corresponding '.d.ts' file. */,
    "declarationMap": true /* Generates a sourcemap for each corresponding '.d.ts' file. */,
    "outDir": "./lib" /* Redirect output structure to the directory. */,
    "strict": true /* Enable all strict type-checking options. */,
    "esModuleInterop": true,
    "experimentalDecorators": true /* Enables experimental support for ES7 decorators. */,
    "emitDecoratorMetadata": true /* Enables experimental support for emitting type metadata for decorators. */,

    /* Advanced Options */
    "forceConsistentCasingInFileNames": true /* Disallow inconsistently-cased references to the same file. */
  },
  "include": ["src"],
  "exclude": ["node_modules", "old", "lib"]
}