tsconfig.json

{
  "compilerOptions": {
    "target": "es5",
    "lib": ["es2015"],
    "outDir": "build",
    "module": "commonjs",
    "strict": true,
    "allowJs": true,
    "checkJs": true,
    "esModuleInterop": true,
    "forceConsistentCasingInFileNames": true,
    "strict": true ,
    "declaration": true,

    "baseUrl": "./",
    "typeRoots": [
        "./node_modules/@types",
        "./build/index.d"
    ],

    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictBindCallApply": true,
    "strictPropertyInitialization": true,
    "noImplicitThis": true,
    "alwaysStrict": true,

    "noUnusedLocals": true,
    "noUnusedParameters": true,
    "noImplicitReturns": true,
    "noFallthroughCasesInSwitch": true,
    "noUncheckedIndexedAccess": true,
    "noPropertyAccessFromIndexSignature": true,

    "allowSyntheticDefaultImports": true,
    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true
  },
  "include": [
      "src/**/*.ts"
  ]
}