tsconfig.json

{
  "compilerOptions": {
    "esModuleInterop":true, 
    
    "alwaysStrict": true,
    "noFallthroughCasesInSwitch":true,
    "noImplicitAny":true,
    "noImplicitReturns": true,
    "noImplicitThis": true,
    "strictFunctionTypes":true,
    "strictPropertyInitialization":true,
    "strictNullChecks": true,
    "strictBindCallApply": true,

    // Output controls.
    "outDir": "./dist",
    "target": "es2018",
    "module": "commonjs",  // module system to use in generated js. commonjs is what is used by node.
    "sourceMap": true,
    "inlineSources": true, // otherwise sourcemaps will refer to the original ts sources, which will have to be served for resolution to work.
    "declaration": true,   // output declaration files (.d.ts)

    // Input controls.
    "rootDir": "./src",
    "moduleResolution": "node", // mechanism for resolving (searching for) modules.

    "lib": [
      "es2018"
    ]
  }
}