State is overwritten in the constructor

I believe the call to initialize state by setting `state` to `initialState` in the constructor subsequently gets overwritten in the next line `this.state = {...}`.

https://github.com/mightyjava/book-rest-api-reactjs/blob/a19c89ba321e9a2c02475a666cc13c07f55ecd4d/src/main/webapp/reactjs/src/components/Book/Book.js#L16



Also, thanks for the excellent tutorial on youtube!