# HP2007: Uncaught error while loading the page

> HP2007 (page error): a script threw an uncaught error while the page loaded. It may or may not be related to hydration. How to read it, fix it or ignore it.

Source: https://hydration.jscrate.dev/docs/issues/hp2007
Last updated: 2026-09-18

HP2007 (`page-error`) means a script threw an error while the page loaded: an
uncaught exception, an unhandled promise rejection, or an error React reported
that is not about hydration. It may or may not be related to hydration. Read the message and stack, and fix the error or confirm
it only happens in the test environment.

| | |
| --- | --- |
| Code | `HP2007` |
| Name | `page-error` |
| Default severity | Warning |
| Group | Problems React reported |
| What it means | A script threw during page load. It may or may not be related to hydration. |

## What HP2007 (`page-error`) means

hydration-proof records every error the page raises while it loads. Errors
that are React hydration messages become HP2xxx codes or evidence for a DOM
finding; everything else becomes HP2007, with the first line of the message as
the finding and the stack as evidence. `console.error` and `console.warn` calls
are not reported this way.

It is a warning by default, since the error may have nothing to do with
hydration. If the same page also has [HP1010](https://hydration.jscrate.dev/docs/issues/hp1010) or
[HP2003](https://hydration.jscrate.dev/docs/issues/hp2003), check whether the error comes from the branch
React re-rendered.

Findings without an element are told apart by their message, so the same error
on the same route has the same fingerprint in every run.

## Likely causes

- Code that assumes data the page does not have in the test environment, such
  as an API that is not reachable or a signed-out user.
- A third-party script that fails in an automated browser.
- A real bug in code that runs on load: an effect, an event listener registered
  on load, a failed `fetch` whose rejection nobody handles.

## How to fix it

1. Open the finding in the HTML report: the evidence has the full stack, and
   the timeline shows which scripts and requests ran before the error.
2. Run `npx hydration-proof test --headed --workers 1 --route /account` to
   watch the page in a real browser window.
3. Fix the error. If it comes from the test environment, give the browser the
   data it needs with a scenario's `mocks`, or sign in with a scenario's
   `login`.

## When the difference is intentional

If the error is known and harmless (a third-party widget that fails without a
network, for example), add an `ignore.issues` rule with `code: "HP2007"`, the
route and a reason, or match its `fingerprint` to ignore only that error. See
[ignoring findings](https://hydration.jscrate.dev/docs/ignoring).

## Example

```text
  ⚠ /account 1.3s  1 warning
    HP2007 Uncaught error while loading the page
      TypeError: Cannot read properties of undefined (reading 'map')
```

## Related

- [HP2002: React warned about a mismatch](https://hydration.jscrate.dev/docs/issues/hp2002)
- [HP2006: the server could not finish a boundary](https://hydration.jscrate.dev/docs/issues/hp2006)
- [Scenarios, sign-in and mocks](https://hydration.jscrate.dev/docs/scenarios)
- [Troubleshooting](https://hydration.jscrate.dev/docs/troubleshooting)