tsconfig.json

{
    "compilerOptions": {
        "strictNullChecks": false,
        "allowSyntheticDefaultImports": true,
        "experimentalDecorators": true,
        "declaration": true,
        "lib": ["es2015", "dom", "dom.iterable", "scripthost"],
        "outDir": "lib"
    },
    "include": [
        "src"
    ]
}