Move from promises to async/await

AuthorApi.js

import delay from './delay';

import { authors } from './authorData'
//This would be performed on the server in a real app. Just stubbing in.

let maxid = authors.reduce(((currentMax, {id}) => currentMax>id ? currentMax : id), 0 );

const generateId = (author) => {
  return ++maxid;
};

const sleep = function (timeout) {
  return new Promise((resolve) => setTimeout(resolve, timeout));
};


class AuthorApi {
  static async getAllAuthors() {
    await sleep(delay);
    return Object.assign([], authors); // so users can change their copy without breaking this list
  }

  static async saveAuthor(author) {
    author = Object.assign({}, author); // to avoid manipulating object passed in.
    await sleep(delay);

    // Simulate server-side validation
    const minAuthorNameLength = 3;
    if (author.firstName.length < minAuthorNameLength) {
      throw new Error(`First Name must be at least ${minAuthorNameLength} characters.`);
    }

    if (author.lastName.length < minAuthorNameLength) {
      throw new Error(`Last Name must be at least ${minAuthorNameLength} characters.`);
    }

    if (author.id) {
      const existingAuthorIndex = authors.findIndex(a => a.id === author.id);
      authors.splice(existingAuthorIndex, 1, author);
    } else {
      //Just simulating creation here.
      //The server would generate ids for new authors in a real app.
      //Cloning so copy returned is passed by value rather than by reference.

      author.id = generateId();
      authors.push(author);
    }

    return author;
  }

  static async deleteAuthor(authorId) {
    await sleep(delay);

    const indexOfAuthorToDelete = authors.findIndex(author => (
      author.id === authorId)
    );

    authors.splice(indexOfAuthorToDelete, 1);
  }
}


export default AuthorApi;

AuthorData.js

var theData = {
	authors: 
	[
		{
			id: '1', 
			firstName: 'Stephen', 
			lastName: 'King'
		},	
		{
			id: '2', 
			firstName: 'J.K.', 
			lastName: 'Rowlings'
		},	
		{
			id: '3', 
			firstName: 'John', 
			lastName: 'Grisham'
		}
	]
};

export default theData;
export var authors = theData.authors;

delay.js

export default 0