JumpStart – History of CI, Intro to MongoDB

CLI

&& vs & (in shell)
&& ( waits for first condition is true)
& (parallel process, runs both whether first condition passes)

to set up env var for both windows and unix
you can use cross-env
there’s also another utility for env var to wait-on command to be finished
npm-run-all CLI tool to run multiple npm-scripts in parallel or sequential

if things get complicated, you can write a shell script to make things easier for you

CI
Old practice: Integrate at the end = PANIC trying to fit the puzzle pieces together
Nightly integration becomes CI
Allows team to discover issues asap
Before commit, all unit tests should pass
never-green (to notify team about CI through a monitor)

Extreme programming – a methodology for developing software

Databases:
Philosophy: Normalization (1NF, 2NF)
Flat files: CSV, Spreadsheets
Relational DB: Using a unique identifier to relate the tables

MongoDB
NoSQL
collection maps to our JS db array, document maps to object
We are using mLab MongoDB addon on Heroku

mongod – daemon (start server)
mongo – shell
interact with mongoDB using: mongo (shell), GUI, VSCode (cosmos)

STEPS:
mongod (in terminal)

mongo (in another terminal)
use db-name-here

in vscode
ctrl-shift-p focus on cosmos db view
attach db account
create database (right-click route (MongoDB) in the attached db account)

in mongo terminal: (if you want to use CLI)
db.users.insert({name: ‘Bob’, address: ‘Cross St’})
db.users.findOneAndDelete()
schema : use mongoose
ORM/ ODM (object relational/ document mapper)
Basically a gatekeeper with an API
prevents wrong data to be inserted

Why MongoDB?
It’s more flexible, and mongoose can be added for schema (adding structure) later on
Good for start-ups/ new products

MONGOOSE (wrapper ard Mongo)
npm i mongoose
use mongoose to start server

MODEL
SCHEMA
(pretty much like joi)

Testing with DB
Testing in jest:
Option 1:  (*not recommended) create a mongoose connection in test.js and then create a separate test db
and beforeAll, delete the collection, by using:

mongoose.connection.db.dropCollection('foo', function(err, result) {...})

Option 2: if you want it to work on CI, use in memory db (https://jestjs.io/docs/en/mongodb)
npm install mongodb-memory-server --save-dev​