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explore / Web & frontend / mozg / React

React · Errors and warnings

Answer questions about a specific React error or warning message: what the message says verbatim, what causes it and how to fix it.

45 notes · updated 2026-08-09 · trained 93%

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https://mozg.sh/mcp --header "Authorization: Bearer …"
> use mozg/react-errors — …
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Ask it things like

answers 26/28 on its latest exam · anti-bluff 2/2
Where am I allowed to call Hooks?Hooks Rules✓
Can I call a Hook inside a conditional statement?Hooks Rules✓
What is the difference between aria-role and role?ARIA Props✓
I'm getting Hook errors even though my code looks correct. What could cause multiple copies of React?Hooks Configuration✓
Is it okay to call Hooks inside useMemo, useReducer, or useEffect?Hooks Rules✓
Can I call a Hook after a return statement?Hooks Rules✓
How do I detect if I'm violating the Rules of Hooks?Hooks Rules✓
Why are my React error messages showing as minified codes instead of descriptive text?Production Error Messages✓

What it can answer

28 coverage checks
93%
Answers 28 of the exam's 30 questions
✓Hooks Rules6 / 6
✓ARIA Props4 / 4
✓Hooks Configuration4 / 4
✓Unknown Prop Warning4 / 4
▲Deprecated APIs3 / 4
▲Production Error Messages2 / 3
✓Special Props2 / 2
✓Server Components1 / 1
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Attacks survived

re-run weekly · 2026-08-09
✓gate-battery12/12 known hostile payloads caught by the ingest gate
✓injection-corpusevery active note scanned — no steering language
✓secret-corpusevery active note scanned — no keys or credentials

heuristic scans against known attack classes — measured and dated, not a promise of unpoisonability

Inside

  • Unknown Prop caused by forwarding props with spread operator · react errors/377
  • Fix Unknown Prop by creating new object and deleting keys · react errors/377
  • Unknown Prop fix example with Object.assign · react errors/377
  • Unknown Prop caused by non-standard DOM attribute · react errors/377
  • Unknown Prop caused by unrecognized React attribute · react errors/377
  • Fix Unknown Prop by destructuring props with spread · react errors/377
  • Unknown Prop warning definition · react errors/377
  • Unknown Prop fix example with destructuring · react errors/377
  • Unknown Prop bad example with spread operator · react errors/377
  • Unknown Prop caused by lowercase component name · react errors/377
  • React recommends migrating from react-test-renderer · react errors/deprecation
  • ReactTestRenderer.create() is deprecated · react errors/deprecation
  • ShallowRenderer no longer exported from react-test-renderer/shallow · react errors/deprecation
  • How to pass a key value into a component · react errors/special-props

Licence

CC BY-NC-SA 4.0

Use it, copy it, build on it, with credit. Selling it is not allowed.