Runtime error when using with react app

[david-wb]

I'm seeing this error on the default example when running inside a react app.

    json_object.ts:60 Uncaught TypeError: Cannot read property 'name' of undefined
    at Book.newValue (json_object.ts:60)
    at Book.set (json_object.ts:85)
    at new JSONObject (json_object.ts:157)
    at new Book (json-models.ts:46)

Here is the code.

class Book extends JSONObject {
    @JSONObject.required
    // @ts-ignore
	name:string
    @JSONObject.optional
    // @ts-ignore
	summary?:string
}

// This is ok
let book:Book = new Book({ name: "Moby Dick" , summary: "You're my obsession" })

And here is my tsconfig

{
  "compilerOptions": {
    "experimentalDecorators": true,
    "emitDecoratorMetadata": true,
    "target": "es5",
    "lib": ["dom", "dom.iterable", "esnext"],
    "plugins": [{ "name": "typescript-tslint-plugin" }],
    "allowJs": true,
    "skipLibCheck": true,
    "esModuleInterop": true,
    "allowSyntheticDefaultImports": true,
    "strict": true,
    "forceConsistentCasingInFileNames": true,
    "module": "esnext",
    "moduleResolution": "node",
    "resolveJsonModule": true,
    "isolatedModules": true,
    "noEmit": true,
    "sourceMap": true,
    "jsx": "react"
  },
  "include": ["src"]
}

Any idea what the problem might be here? Thanks!