TypeScript error TS2345 Argument type not assignable
This error matches known, documented patterns with reliable solutions.
Quick Fix (Most Common Solution)
- Check expected type
- Add null check
Seeing "TypeScript error TS2345 Argument type not assignable"? This error can be frustrating, but it's usually fixable. It typically affects your development workflow or system. Below you'll find clear, step-by-step solutions to resolve this issue.
What This Error Means
The value you are passing does not match the expected type.
Frequently documented in developer and vendor support forums.
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Common Causes
- Wrong type passed
- Null not handled
- Union type not narrowed
How to Fix
- Check expected type
- Add null check
- Use type narrowing
Last reviewed: March 2026 How we review solutions
Optional follow-up
Some users ask whether saving fixes for recurring errors would be useful when the same issue appears again.
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Frequently Asked Questions
How do I narrow union types?
Use typeof, instanceof, or type guards.
Why is null a problem?
Strict null checks require explicit null handling.
Related Resources
Also Known As
- Node.js error
- Node runtime error
- JavaScript server error
- Node exception
Common Search Variations
- "node js error fix"
- "node command not working"
- "node app crashing"
- "javascript server error solution"
- "node runtime crash fix"
- "how to debug node error"
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