jomb

just organize my books - library management app

to start

1. create /jomb/server/config/dev.json file with the following boilerplate:

{
  "DBHost": ""
}

Add your MongoDB connection string. You can also add a test.json file in this folder to run the backend tests.

2. cd into /jomb/client and run npm install
3. cd into /jomb/server and run npm install, then run yarn dev or npm run dev to boot up both express and react servers.

---

Adding Change History Event to an Existing Endpoint

Add Change History middleware to server.js routing

const { addChangeHistoryEvent } = require("./handlers/changeHistory");
...
app.route("/api/book").post(bookController.addBook, addChangeHistoryEvent);

The action that addChangeHistoryEvent will add to the database is defined within bookController.addBook, so we don't need to worry about it here.

Next, let's update the bookController.addBook method to implement next(). Only add next() when express should continue to add a change history log (ie: on success only).

exports.addBook = async (req, res, next) => {
  // all the logic of adding a book and error handling
  // then we add the necessary data to the request
  // and send it on to the addChangeHistoryToBook method.
  // errorNumber, message, and book will be sent to the UI
  // action and description are used to add the
  // change history to the mongo table they are stored in
  req.transportToUI = {
    errorNumber: SUCCESS,
    message: "Book successfully added!",
    book
  };
  req.changeHistoryData = {
    description: ADD,
    detail: "Added book to library",
    bookId: book._id
  };
  next();
}

Everything within the transportToUI object will be passed back to the UI via res.json() in the addChangeHistoryEvent method.

The addChangeHistoryEvent will return an object like below to the UI:

{
    "transportToUI": {
        "errorNumber": 0,
        "message": "Book successfully added!",
        "book": {
            "authors": [
                "Kim Golombisky",
                "Rebecca Hagen"
            ],
            "tags": [],
            "location": [],
            "_id": "5b9eac7855ce51144c74885b",
            "isbn": "1138804649",
            "addedOn": "2018-09-16T19:18:16.729Z",
            "title": "White Space Is Not Your Enemy",
            "__v": 0
        }
    },
    "changeHistory": {
        "errorNumber": 0,
        "message": "Successfully added change history event to book"
    }
}

Possible Error Numbers to Check For

See the jomb/server/models/constants.js file for an up-to-date list of error numbers