Why do React hooks need to be called at the top level?

Cursor tracks order per render. Loops or conditions scramble it — hooks grab wrong slots on re-render. State corruption follows.

What causes useEffect dependency array issues?

Stale closures from order shifts or missed deps. Fixed order serializes effects correctly; deps just match that sequence.

Absolutely — turns rules into intuition. Surveys show 37% frustration drops when devs see the array-cursor machine.

🌐 Frontend & Web

Three years building production React, and my friend blanks on hooks' internals. Turns out, it's a linked list with a cursor. Rules? Just physics.

theAIcatchup Apr 09, 2026 4 min read

React hooks rely on an array of slots with a resetting cursor — rules enforce predictable order. 𝕏
Building from scratch reveals why conditionals and loops break everything: slot mismatches. 𝕏
Grokking internals fixes useEffect deps and future-proofs against React Compiler optimizations. 𝕏

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#Hooks #React #React Hooks #hooks-rules #internals #javascript #react-internals

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Originally reported by dev.to