tsconfig.json

{
  "compilerOptions": {
    "target": "es6", /* Specify ECMAScript target version: 'ES3' (default), 'ES5', 'ES2015', 'ES2016', 'ES2017','ES2018' or 'ESNEXT'. */
    "module": "commonjs", /* Specify module code generation: 'none', 'commonjs', 'amd', 'system', 'umd', 'es2015', or 'ESNext'. */
    "allowJs": false,                       /* Allow javascript files to be compiled. */
    "checkJs": false,                       /* Report errors in .js files. */
    "declaration": true, /* Generates corresponding '.d.ts' file. */
    "outDir": "./build", /* Redirect output structure to the directory. */
    "strict": true, /* Enable all strict type-checking options. */
    "noImplicitAny": true, /* Raise error on expressions and declarations with an implied 'any' type. */
    "strictNullChecks": true, /* Enable strict null checks. */
    "strictFunctionTypes": true, /* Enable strict checking of function types. */
    "strictPropertyInitialization": true, /* Enable strict checking of property initialization in classes. */
    "noImplicitThis": true, /* Raise error on 'this' expressions with an implied 'any' type. */
    "alwaysStrict": true, /* Parse in strict mode and emit "use strict" for each source file. */
    "noUnusedLocals": true, /* Report errors on unused locals. */
    "noUnusedParameters": true, /* Report errors on unused parameters. */
    "noImplicitReturns": true, /* Report error when not all code paths in function return a value. */
    "noFallthroughCasesInSwitch": true, /* Report errors for fallthrough cases in switch statement. */
    "moduleResolution": "node",            /* Specify module resolution strategy: 'node' (Node.js) or 'classic' (TypeScript pre-1.6). */
    "esModuleInterop": true, /* Enables emit interoperability between CommonJS and ES Modules via creation of namespace objects for all imports. Implies 'allowSyntheticDefaultImports'. */
    "experimentalDecorators": true, /* Enables experimental support for ES7 decorators. */
    "emitDecoratorMetadata": true, /* Enables experimental support for emitting type metadata for decorators. */
  },
  "exclude": [
    "tests",
    "build"
  ]
}