Coding

Recommendations and practices.

General

Don't use var, as this is for old browsers
Use const unless you plan to change a variable, in which case use let
JS file naming, use .mjs for module-based ES6 JS. If you use JS then you will have to set your package to use modules type: module
Use the AXIOS library for HTTP calls from the server, and the JS built-in FETCH library for client side JS. (Axios has more features)
Check input data accuracy by validating inputs (eg. regular expression or other checks) This is checking the integrity of data, not checking for security issues.
Return appropriate status codes and error message for API calls
Could use the HE (NPM JS) library for encoding inputs and escaping output

Always sanitise inputs at server and client input interfaces
Always parse outputs. This includes reads and writes from databases and external services, too.
Try to log important operations fopr security and debugging
Never output a stack trace in production

Practice coding by doing a simple app. Put it in GitHub and learn as you code. Start small!
Don't be afraid to refactor. When you see something a bit smelly, and you have time, redo it.
Are your functions doing only one thing? If not, seperate concerns and refactor
Every database table should have a primary key
Always implement appropriate error handling (try-catch) for any operation with a posibility of failure.
Write unit tests FIRST, before you write your code
Document code appropriately. Classes, functions, and then anything that is worth explaining. Don't add comments for the sake of commenting
If you have to code a manual operation more than once in your code, put it in a seperate function of class
Optimised code is great for efficiency, but can be bad for readability. Be efficient, but also keep things simple when it makes sense.
Good error handling means faster debugging.
Efficient database usage keeps things responsive. Watch for:
- Connection pool exhaustion
- Slow queries blocking requests
- Connections not being closed
Plan for the failure of external dependencies
Clear, structured logs give clarity to your application operations.
Timeouts protect your system from cascading failures.
Double check configurations across environments. (environment variables and configuration)
External calls can overload your application. Include rate limiting and traffic control.

Everything is in containers today, so create a Dockerfile and package into an image. If you are using GitHub, you can build simple automations to build Docker images and deploy these to Docker Hub.