JustNode.js

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Starting a new node project:

1. install node and nvm

2. Create a directory for your project and cd to that directory.

3. perfrom: $ npx gitignore node $ npm init -y

   ** the first command creates a .gitignore file for node ** the second command creates an initial package.json for your project ===================================

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Chapter 10 - Using a Database

In this chapter I have used postgresql which I Installed with a docker container brought up with docker compose.

There is a documentation at https://node-postgres.com/features/connecting,
on how to create a client, connection pool and how to query the data base.

1. Installed a postgres sql connector for node:

   $ npm install --save pg

   Now, if you decide to use a different DB , please install the corresponding connector.

2. Created a buildDB.sql (see util/sqlScripts) to build the initial database tables if do not exist already, and seed some data.

3. Connecting to DB (util/database.ts: 10.1): As described in the documentation I specified, there are several ways to connect to db: via a single client which connect to db with every query, or via a connection pool which holds a pool of connections and which can be used to retrieve connection to use for a query. Using a pool is more efficient way. Also, as described in the documentation, connection information can be specified with:

   A. environment variables, for example:

    export PGHOST='localhost'  
    expport PGUSER='myusername'  
    export PGDATABASE=postgres  
    export PGPASSWORD=mypassword  
    export PGPORT=5432  
   

   B. Specifying connection information in the code as configuration.

   C. Specifying a connection string in the code.

   Note: B and C may expose sensitive information in the code.

4. Domain object (models/post.ts: 10.2): Shows how to create a domain object with CRUD operations for the Post table.

5. Querying data - the controller methods (feedController.ts) were modified to use the CRUD methods from the domain object to query data from the Post table, and return data in json format to the client, as a response of the http request.

6. Added postman test collection use the test directory to test the GET and POST end points. A curl version of these http calls is in the same directory.

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Chapter 11.1 - Using Sequelizer (ORM) for db instantiation

References:
https://www.npmjs.com/package/sequelize-typescript
https://sequelize.org

1. installed sequelize:
   $ npm install --save sequelize reflect-metadata sequelize-typescript
   $ npm install --save-dev @types/node @types/validator
   (a prerequisite for this library is a db driver specific for your db, which we already installed in the last chapter)
2. database.ts (11.1.1): Instantiate a connection to the db using the sequelize object.
3. post.js (11.1.2): create a sequelizer model (domain object) for the post table.
4. app.js (11.1.3) - sync the db with all models defined for the db( creates tables if does not exist)

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Chapter 11.2 - Adding CRUD operations using Domain objects with Sequelizer

1. feedControllers.ts (11.2.1) : update controllers to perform CRUD operations (here : read (findAll) and create).