tsconfig.json

{
    "compilerOptions": {
        "baseUrl": ".",
        "outDir": "lib",
        "module": "commonjs",
        "target": "es2017",
        "lib": ["es6", "dom", "es2017"],
        "sourceMap": true,
        "allowJs": false,
        "moduleResolution": "node",
        "rootDir": "src",
        "forceConsistentCasingInFileNames": true,
        "noImplicitReturns": true,
        "noImplicitThis": true,
        "noImplicitAny": false,
        "strictNullChecks": true,
        "suppressImplicitAnyIndexErrors": true,
        "noUnusedLocals": true,
        "importHelpers": false,
        "esModuleInterop": true,
        "declaration": true,
        "downlevelIteration": true,
        "resolveJsonModule": false,
        "types": ["jest", "node"]
    },
    "include": [
        "src/**/*"
    ],
    "exclude": ["node_modules", "lib", "test", "**/demo.ts"]
}