Tips, Fixes & Bugs
Bite-sized developer lessons you can read in under a minute. Fresh content every day — tips, 1-min fixes, and real bug breakdowns, straight to the point.
Latest from each series
Stop Using map() for Side Effects
Using Array.map() for side effects leads to confusing code and unnecessary memory usage.
Fix “Too Many Re-renders” Error in React
This error happens when your component keeps updating state inside render, causing an infinite loop.
API Returns Cached Data Even After Update
Your API returns old data even after updating records due to caching issues in browser, CDN, or server.
New content drops daily. A fresh tip, fix, or bug breakdown every day — bookmark this page to stay sharp.
Today's challengeAll tips & fixes
19 itemsDaily Dev Tips
8Don’t Hide Errors Behind Generic Toasts
A “Something went wrong” message helps nobody. Log the real error and show users what they can do next.
Always Add Timeouts to External API Calls
Never call external APIs without a timeout — one slow dependency can freeze your entire system.
Validate Request Payloads at the API Boundary
Never trust incoming request data. Validate it at the API boundary before it touches business logic or the database.
Stop trusting “it works on my machine”
If a fix only works on your laptop, it is not a fix. It is a temporary illusion.
Avoid Hardcoding API URLs — Use Environment Variables Properly
Hardcoding API URLs makes your app hard to manage across environments. Use environment variables for flexibility and security.
Array Deduplication Challenge (3 Ways)
Can you remove duplicate values from an array using 3 different approaches in JavaScript?
1-Min Fixes
6Fix API Calls Running Twice in React Strict Mode
React Strict Mode can call effects twice in development. Add a guard or make your API action idempotent.
Fix “map is not a function” Quickly
This usually happens when you think a value is an array, but it is actually undefined, null, or an object.
Add loading guard to stop duplicate API calls
One missing loading check can create duplicate records, double payments, or repeated requests.
Fix “Cannot read properties of undefined” instantly
This error happens when you access a property on undefined. Use optional chaining to fix it quickly.
Fix Port Already in Use Error Instantly
Quickly free up a busy port and restart your server without wasting time debugging.
Fix CORS Error in 1 Line (Express.js)
Quickly fix CORS errors in your API by enabling cross-origin requests with a simple middleware.
Bug Breakdowns
5Pagination Worked… Until Data Changed
Pagination broke in production because page numbers were used instead of stable identifiers.
Search Worked Locally but Failed in Production
A search feature worked perfectly on local data but failed in production because matching was case-sensitive in one environment and inconsistent in real records.
API Working in Postman but Failing in Browser
API works in Postman but fails in browser due to missing CORS configuration.
Why useEffect Runs Twice in React (Not a Bug)
If your useEffect runs twice in development, it is due to React Strict Mode and not an actual bug.
API Returning 500 Randomly (Async Bug You Might Be Ignoring)
Random 500 errors often come from unhandled async errors that silently crash your request flow.