TypeScript Type Errors: Fixes for Next.js Developers
Every fix here traces the error back to the type-system rule that produced it, not just the one-line patch — so the same class of error is recognizable the next time it shows up under a different message.
Compiler errors
5 itemsTypeScript Getter Setter Errors: TS1056, TS1028, TS2378 Fix
Seeing TS1056, TS1028, or TS2378? Set "target": "ES5" in tsconfig.json ? TypeScript accessors require ES5+ to compile to Object.defineProperty.
Fix TS7016: Could Not Find Declaration File for Module
TS7016 means the JS package ships no types and no @types/* exists. Three fixes ranked: install @types, write a local .d.ts, or use declare module.
Fix TS2305: Module Has No Exported Member in TypeScript
"Module 'X' has no exported member 'Y'" (TS2305) usually means a default-vs- named import mismatch, a CommonJS interop gap, or a stale @types version.
TS2564: Why Constructor Methods Don't Count as Init
TS2564 fires because strictPropertyInitialization never analyses methods called from the constructor — only direct assignments count. Five fixes, ranked.
Fix "Property does not exist on Window" in TypeScript
Resolve TypeScript errors when assigning custom properties to window by extending the Window interface with declaration merging.
Type patterns & operators
4 itemsTypeScript ! Operator: Fix Object Is Possibly Undefined
What the ! operator does in TypeScript, why it causes "Object is possibly undefined" errors, and how to replace it safely.
How to Convert a String to Number in TypeScript: 2026 Fix
Fix silent NaN errors when converting strings to numbers in TypeScript. Learn explicit parsing, type narrowing, and runtime validation.
Interfaces vs Types in TypeScript: 2026 Best Practices
Clarify when to use interfaces vs types in TypeScript for scalable production apps — with concrete examples and real-world tradeoffs.
JSX.Element vs ReactNode vs ReactElement: TS2322 Fix
Use ReactNode for props and return types — it accepts null, strings and arrays; JSX.Element and ReactElement don't. Fixes TS2322 assignability errors.
Other hubs
Next.js + Supabase: The Complete Resource Hub
Everything you need to build production-ready full-stack apps with Next.js 15 and Supabase — authentication, RLS, deployments, performance, and architecture decisions.
Supabase Debugging & Troubleshooting Hub
Field-tested fixes for the Supabase errors that actually waste your time: RLS silent failures, session persistence, slow queries, realtime gotchas, and auth redirects.
n8n Automation: Real Workflows from Real Projects
Practical n8n automation guides built from actual client work — CRM lead capture, client reporting, Zapier migration, silent failure debugging, and self-hosted AI with Ollama.
PostgreSQL in Production: Errors, Auth & Query Patterns
PostgreSQL error messages and query patterns you hit running Postgres in production — whether you connect through psql directly or through Supabase, the underlying database is the same.