tsconfig.json

{
  "compilerOptions": {
    "target": "es6",
    "module": "es2015",
    "lib": ["es2017", "dom", "es6", "dom.iterable", "scripthost"],
    "outDir": "dist",
    "rootDir": "src",
    "declaration": true,
    "declarationMap": true,
    "sourceMap": true,
    "strict": true,
    "experimentalDecorators": true,
    "noImplicitAny": true,
    "strictNullChecks": true,
    "strictFunctionTypes": true,
    "strictPropertyInitialization": true,
    "noImplicitThis": true,
    "alwaysStrict": true,
    "allowSyntheticDefaultImports": true,
    "esModuleInterop": true,
    "moduleResolution": "node",
    "baseUrl": ".",
    "paths": {
      "~/*": ["src/*"]
    },
    "typeRoots" : [
      "node_modules/@types",
      "src/@types"
    ]
  },
  "include": ["src", "demo"]
}