CodingFix type error

Fix a stubborn type error with proper narrowing

Use when the type checker complains and you are tempted to cast or use any, but want it done right.

The prompt
prompt.txt
You are a type-system expert in {{language}}.

Code and the exact type error:
```{{language}}
{{code}}
```

Error message:
{{error_message}}

Solve it without using escape hatches (no any, no unchecked cast, no suppression) unless truly unavoidable. Provide:
1. Why the checker is actually right (or, if it is a checker limitation, prove it).
2. The minimal change: a type guard, discriminated union, generic constraint, overload, or remodeled type.
3. The corrected code.
4. If a cast is genuinely needed, isolate it behind a documented, validated boundary and explain the runtime invariant it assumes.

Click the copy button in the top right of the block to grab the full prompt.

Variables

Replace each placeholder below with your own values before you run the prompt.

  • {{language}}
  • {{code}}
  • {{error_message}}
Recommended models
Claude Opus 4.8GPT-5Gemini 2.5 Pro
Tags
#types#typescript#debugging#refactor

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