Debugging and Stopping Infinite Render Loops in React

Infinite renders are not magic bugs — they are deterministic feedback loops. Once you understand why a render retriggers itself, they become easy to reproduce, debug, and prevent.

This post walks through a step‑by‑step mental model to stop the “Maximum update depth reached“ errors for good.

What an Infinite Render Loop Really Is

At its core, an infinite render loop looks like this:

Component renders
Some reactive logic runs (effect, watcher, computed, subscription)
That logic updates the state
State update causes a re-render
Repeat forever

The key insight:

Renders don’t loop by accident — they loop because state changes on every render.

The Fastest Way to Reproduce the Bug

When debugging, your first goal is reproduction.

Minimal reproduction checklist

Comment out everything except one state value and one reactive hook (effect/watcher). Then add a log in both render and state update.

Example:

function Component() {
  console.log('render');

  const [count, setCount] = useState(0);

  useEffect(() => {
    console.log('effect');
    setCount(count + 1);
  }, [count]);
}

If you see:

render → effect → render → effect → ...

You’ve confirmed the loop.

The #1 Root Cause: Unstable References

Most infinite loops come from reference instability, not logic errors.

Identity vs Equality

{} !== {}
[] !== []
() => {} !== () => {}

Even if values look equal, their identity changes on every render.

Example: Object in dependencies

function Component({ userId }) {
  const filters = { active: true, userId };

  useEffect(() => {
    fetchData(filters);
  }, [filters]); // ❌ new object every render
}

This results in the effect that runs forever.

Stabilizing References with Memoization

Fix with memoization

const filters = useMemo(() => ({
  active: true,
  userId
}), [userId]);

Now, it has the same reference, but the effect runs only when userId changes. A rule of thumb is that if a variable goes into the dependency array, it must be referentially stable.

Choosing Correct Dependencies (Not Fewer)

A common anti-pattern:

useEffect(() => {
  if (status === 'loaded') return;
  setStatus('loaded');
}, [status]);

This effect updates its own dependency once, then converges to a stable state instead of looping forever.

Linting That Actually Helps

Linting is one of the cheapest ways to prevent infinite render loops before they reach runtime — especially in React and Next.js apps.

By specifying the correct React Hooks Rules, you can catch the most common causes of render loops. BY using correct linting rules, you can enable rules in your editor. For example:

react-hooks/rules-of-hooks
react-hooks/exhaustive-deps

This forces correct dependency lists, exposes unstable references early, and prevents stale closures disguised as "fixes".

But still, the warnings about missing dependencies are not always true. It makes sense to treat them as design bugs, not suggestions.

Debugging with `why-did-you-render` + LLMs

Although we are talking about this step at the very last, if time is crucial to you, then this could be the first resort.

Sometimes you know a component is re-rendering too much, but you don’t know what changed. Multiple states or effects might be responsible for an infinite render loop.

This is where why-did-you-render becomes extremely powerful — especially when paired with an LLM.

What `why-did-you-render` does

why-did-you-render monkey-patches React in development and logs exact reasons for re-renders:

Which props changed
Whether the change was by identity or value
Which hooks triggered the update

Instead of guessing, you get concrete evidence.

Basic setup

[why-did-you-render]
MyComponent re-rendered because of props changes:
  props.filters changed
    prev: { active: true, userId: 1 }
    next: { active: true, userId: 1 }
  reason: props.filters !== prev.props.filters

This immediately tells you:

The values are equal, but the reference is not
Memoization is missing

Feeding logs to an LLM (Copilot / ChatGPT)

Here’s where debugging gets much faster.

You can save the console logs as a .log file and feed them to the LLM agent along with the code context that you feel might be the reason for the infinite rendering. You can use the following prompt:

"I have attached the console logs from why-did-you-render along with the code in which the infinite loop is happening. Can you find what is causing this behaviour and how do I stabilize it?"

Because the logs already encode identity vs equality, the LLM can:

Identify unstable objects/functions
Suggest correct useMemo / useCallback placement
Detect unnecessary props drilling
Recommend architectural fixes (lifting state, memo boundaries)

This removes the guesswork that usually slows humans down.

Why this works so well with LLMs

LLMs struggle with implicit runtime behavior.

why-did-you-render turns runtime behavior into explicit text.

Once behavior is textual:

Debugging becomes a reasoning problem — which LLMs are good at.

Used together, they form a tight loop:

Reproduce the render issue
Capture why-did-you-render logs
Paste logs + code into an LLM
Apply fix
Verify render stability

Final Thought

Infinite render loops are not a framework flaw — they are a signal.

They tell you that:

Data flow is unstable
Identity is misunderstood
Or side effects are misplaced

Once you respect reference stability and dependency correctness, infinite loops disappear — permanently.