nosql-demo

This is a small repo for some very simple exercise / demos for usage of a NoSQL DB - pouchdb

Project setup

Prerequisite

1. node (tested version: v8.17.0)
2. yarn (tested version: 1.22.4)

(Note: yes, pouchdb does NOT need to be installed separately because it is a pure JavaScript implemented NoSQL DB and would be installed when you run yarn to install the npm dependencies. Hurrah! 🎉)

Setup steps

Check out this repo and run the following at the project root:

1. yarn

Check project setup

If the project is setup correctly, you should be able to run the following:

1. yarn jest - this would run all the tests under the project (but by default you should see all tests being red because this is the exercise - fix all of them! :-) )
2. yarn ts-node src/typescript/playground.ts - this would run the playground.ts which is a, well, playground sandbox that you can mess around - feel free to experiment the pouchdb APIs there!

Exercise

Context

As mentioned in the deck, we would like to retrieve some data from and write some data to the pouchdb database.

The "spec" / "requirements" can be found at the /src/typescript/systemDesignExercise.test.ts - unfortunately the tests are all red right now.

Can you please fix them? 🐱

Checking

We can run the tests by running: yarn jest

And you should be able to see the test results.

Caveat

For simplicity, I had used the pouchdb-adapter-memory plugin for pouchdb so the databases created in the exercise are transient and stored in-memory (and thus would be reset for each run).

If you want to see how to persist the data (e.g. in files), feel free to take a look at /src/typescript/fileBasedDatabaseExamples.ts

Need help?

Feel free to chat / slack me or shout in the slack group.

Or you may want to take a look at the pouchdb documentations (trust me, they are pretty well-written):

1. API
2. Learn
3. Guides
4. Blogs
   1. A very good blog by pouchdb creator about promise

Folder Structure

You can find all the source files you need under src folder.

In particular, you might want to look at the following files:

1. /src/typescript/systemDesignExercise.ts + /src/typescript/systemDesignExercise.test.ts - these are the exercise files
2. /src/typescript/playground.ts - this is a sandbox code which you can change and quickly test out the APIs
3. /src/typescript/fileBasedDatabaseExamples.ts - this is an example usage of file-based pouchdb database - if you run this file, a folder pouchdb_database would be created with some pouchdb data files created inside

Feel free to ignore the other files such as package.json, yarn.lock, jest.config.js for now (mainly for project configuration)