tsconfig.npm.json

{
  "files": ["project/main.ts"],
  "compilerOptions": {
    "rootDir": "project/",
    "noImplicitAny": true,
    "target": "ES2020",
    "module": "ES2020",
    "moduleResolution": "node",
    "downlevelIteration": true,
    "declaration": true,
    "declarationDir": "./lib/",
    "outDir": "./lib/"
  }
}