Events app

Tech used

Frontend:

• Language: JavaScript
• Vue.js
• Apollo Client
• vue-apollo
• graphql-tag (gql)

Backend:

• Language: Typescript
• Node.js
• Apollo Server with NestJs
• PostgreSQL: pg & pgTyped

Setup

Server side:

# In /server
npm i
npm run generate

# Local db setup
docker run --name some-postgres -e POSTGRES_PASSWORD=mysecretpassword -p 5432:5432 -d postgres
docker cp db.sql some-postgres:docker-entrypoint-initdb.d/db.sql
docker exec -u postgres some-postgres psql postgres -f docker-entrypoint-initdb.d/db.sql

npm start

Client side:

# In /client
npm i

npm run serve

Improvements needed

Due to spending a fair amount of time getting the client side setup (first time using vue & apollo), I was short on time to do some things.

General: Have a way to setup server & client through a simple command (using lerna for example).

Backend:

• Add various level of descriptions to explain data & the business rules.

• Error handling: creating domain specific errors depending on which part of the app fails (+ logging).

• Refactoring db queries a bit.

• Current way of handling event pagination is simple, but is not performant & has multiple edge cases including the showMore computing: should implement relay paging.

• Externalize configuration (server & database) to make the app more prodution ready.

• Tests:

  • Not needing the db to be up for all tests.
  • Adding tests using the status filter + paging.
  • Units tests on the service level for business logic.
  • Testing sql queries.
  • Error cases (queries failing, invalid input, etc...).

• Performance:

  • Only call getClosestSessionStartInfo() queries once per event.
  • Try to look at a rewrite of the getLatestEventsWithEventMessagesCountByStatus() query to find another way than using a second LEFT JOIN, which impacts the performance.

• Providing a docker-compose.yml to setup the db easily.

Client:

• Missing proper code composition, everything was done hastly.
• No documentation & tests.
• Improve error handling by displaying a message or highlight the text input on creation.
• Should optimistically update the event lists on new event creation.
• Should look into using Apollo components (ex: ApolloQuery, ApolloMutation).