Software architect. Web Development, build apps with Angular, TypeScript, JavaScript, and NestJS
Reading Time: 7 minutes Introduction When I create nestjs project to do proof of concept, I usually spend the first hour to install dependencies and add rules to eslintrc.js before writing any meaningful code. When I researched code generation in nestjs, I found out that angular schematics can author nestjs library to upgrade configurations and add new files. Therefore, … Read more
Reading Time: 5 minutes Problem: Frontend developers complained that integration with API is a painful process because there is no documentation on available endpoints, expected payloads and responses. Therefore, our backend team leads elect to enable swagger such that frontend developers can browse all the APIs on dedicated documentation site. When they showed me how it was done, I … Read more
Reading Time: 7 minutes Scenario: Our ESG (Environmental, Social, and Governance) platform requires to run schedule jobs to call endpoints to generate reports for internal teams and send company emails to our customers. Development team was tasked with developing a job scheduler that executes cron jobs at a specified period of time. node-cron is a popular open source library … Read more
Reading Time: 6 minutes Scenario: Our ESG (Environmental, Social, and Governance) platform offers monthly and annual subscriptions to charge customers for using our ESG reporting service. When we designed our payment module, we chose Stripe as our payment platform because it accepts credit card payment method, provides good documentations and open source node library for the API (stripe-node). Problem: … Read more
Reading Time: 3 minutes Scenario: Application at work stores data lists in database tables and they never change after initial population. These data lists are used for dropdown selection in frontend, for example, users select their salutation in user profile page and click to make the change. Problem: When user opens the page, UI makes a HTTP request to … Read more
Reading Time: 4 minutes This is part 3 of Use TypeOrm Custom Repository in NestJS and this post is about end- to-end testing (e2e) of NestJS endpoints. In part one and part two, controllers, services and custom repositories are tested and they pass all the test cases. The final step is to validate HTTP requests between frontend and backend … Read more
Reading Time: 5 minutes This is part 2 of Use TypeOrm Custom Repository in NestJS and this post is about unit testing custom repository. In part one, I created a NestJS demo with controllers, services and custom repositories. The demo also added unit testing on controllers and services in which I mocked the methods of custom repositories with jest.fn(). … Read more
Reading Time: 3 minutes When developers start using NestJS, they create new module with controllers and services to design backend APIs. Developers register controllers and services in the module and inject service into controller to perform CRUD operations. Provider Registration The following is a code snippet of a user module; user controller is registered in controller array while user … Read more
Reading Time: 5 minutes NestJS has out of box integration with TypeORM, a TypeScript and JavaScript ORM that has good support of PostgreSQL. The library offers decorators to model data types and entities and tools to generate migration scripts to update database schema; therefore, it is a popular choice to perform CRUD operations. TypeORM offers custom repository that allows … Read more
Reading Time: 2 minutes We use NestJS at work and the backend project needs to perform date calculations and formatting in the services. Our team chose momentJS because it is the one of the most popular date-time open source project. After a while, we discovered that the library size is huge (~290kb) and it is not tree-shakable. If I … Read more