tsconfig.json

{
  "compilerOptions": {
    "module": "commonjs",
    "target": "es5",
    "noImplicitAny": true,
    "noUnusedLocals": true,
    // TODO(rsgowman): enable `"strict": true,` and remove explicit setting of: noImplicitAny, noImplicitThis, alwaysStrict, strictBindCallApply, strictNullChecks, strictFunctionTypes, strictPropertyInitialization.
    "noImplicitThis": true,
    "alwaysStrict": true,
    "strictBindCallApply": true,
    //"strictNullChecks": true,
    "strictFunctionTypes": true,
    //"strictPropertyInitialization": true,
    "lib": [
      "es2015",
      "esnext.asynciterable"
    ],
    "outDir": "lib",
    // We manually craft typings in src/index.d.ts instead of auto-generating them.
    // "declaration": true,
    "rootDir": "."
  },
  "files": [
    "src/index.ts"
  ]
}