tsconfig.json

{
    "compilerOptions": {
        "target": "ES2020", // build project compiles to es2017 syntax
        "module": "CommonJS", // babbel, webpack has transpiler to work with commojs
        "outDir": "./dist", // lib folder will be created where compiled file are placed. 
        "types": ["node", "jest"],
        "moduleResolution": "Node10",
        "declaration": true, // type defination are automatically placed into a particular file while building
        "strict": true,
        "resolveJsonModule": true,
        "esModuleInterop": true,
        "removeComments": true,
        "noImplicitAny": true,
        "strictNullChecks": true,
        "isolatedModules": true,
        "noEmit": true,
    },
    "include": ["src", "src/errorHandler/t.ts"], // compile our ts code present in /src
    "exclude": ["node_modules", "**/tests/*"], // usual convention to test the lib is present in **/
  }