tsconfig.json

{
  "compilerOptions": {
    // https://github.com/microsoft/TypeScript/wiki/Node-Target-Mapping
    "target": "ES2015",
    "module": "ES2015",
    "lib": ["ESNext", "DOM"],
    "allowJs": false,
    "declaration": true,
    "outDir": "./build",
    "rootDir": ".",
    "importHelpers": false,

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

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

    "moduleResolution": "node",
    "esModuleInterop": true,
    "resolveJsonModule": true,

    "skipLibCheck": true,
    "forceConsistentCasingInFileNames": true,
    "noImplicitOverride": true,
    "useUnknownInCatchVariables": true
  }
}