Basic typescript.config file, with explanations

basic-ts-config

{
  "compilerOptions": {
    // project options
    "lib": [
      "ESNext",
      "dom"
    ], // specifies which default set of type definitions to use ("DOM", "ES6", etc.)
    "outDir": "lib", // .js (as well as .d.ts, .js.map, etc.) The directory where your files will be created
    "removeComments": true, // Strips all comments from TypeScript files when converting to JavaScript
    "target": "ES6", // Target environment

    // Module resolution
    "baseUrl": "./", // Lets you set a base directory to resolve non-absolute module names
    "esModuleInterop": true, // fixes some issues TS originally had with the ES6 spec where TypeScript treats CommonJS/AMD/UMD modules similar to ES6 modules
    "moduleResolution": "node", // Pretty much always Node for modern JS. Other option is "classic"
    "paths": {}, // A series of entries which re-map imports to lookup locations relative to the baseUrl

    // Source Map
    "sourceMap": true, // enables the use of source maps for debuggers and error reporting, etc.
    "sourceRoot": "/", // Specify the location where a debugger should locate TypeScript files instead of relative source locations

    // Strict Checks
    "alwaysStrict": true, // Ensures that your files are parsed in the ECMAScript strict mode, and adds “use strict” to each source file
    "allowUnreachableCode": false, // pick up dead code paths
    "noImplicitAny": true, // TypeScript will fall back to a type of any for a variable when it cannot infer the type
    "strictNullChecks": true, // When strictNullChecks is true, null and undefined have their own distinct types and you’ll get a type error if you try to use them where a concrete value is expected

    // Linter Checks
    "noImplicitReturns": true,
    "noUncheckedIndexedAccess": true, // accessing index must always check for undefined
    "noUnusedLocals": true, // Report errors on unused local variables
    "noUnusedParameters": true // Report errors on unused parameters in functions
  },
  "include": ["./**/*.ts"],
  "exclude": [
    "node_modules/**/*"
  ]
}