Error map
not wrapped in act Warning: An update to Component inside a test was not wrapped in act(...)
React · layer 1, On your device
Centre: this error. First ring: errors it is linked with (12). Outer ring: what those are linked with. Colours show the layer of a request each error belongs to. Click any dot to re-centre the map on it; hover to follow its connections. The centre dot opens the error page.
Directly related (12)
Error: useNavigate() may be used only in the context of a <Router> component.
A React Router hook ran in a component that isn’t rendered inside a Router provider.
Jest: SyntaxError: Cannot use import statement outside a module (Jest encountered an unexpected token)
Jest tried to run untransformed ES module syntax — usually from a dependency in node_modules.
Node.js: [UnhandledPromiseRejection] — This error originated either by throwing inside of an async function without a catch block
A promise rejected and nothing handled it; since Node 15 this crashes the process.
Error: No QueryClient set, use QueryClientProvider to set one
TanStack Query hooks ran outside a QueryClientProvider (or a duplicate copy of the library is installed).
SyntaxError: await is only valid in async functions and the top level bodies of modules
await was used inside a function that isn’t async (or in a classic, non-module script).
AbortError: The user aborted a request. / signal is aborted without reason
A fetch was cancelled through an AbortController (or the browser cancelled it).
TypeError: Failed to execute 'json' on 'Response': body stream already read
A fetch Response body was consumed twice (e.g. calling .text() then .json()).
RuntimeWarning: coroutine 'fetch' was never awaited
An async function was called without await, so it never ran.
Warning: validateDOMNesting(...): <div> cannot appear as a descendant of <p>.
The JSX produces invalid HTML nesting, which also causes hydration mismatches in SSR.
Warning: Function components cannot be given refs. Attempts to access this ref will fail. Did you mean to use React.forwardRef()?
A ref was passed to a function component that doesn’t forward it.
Error: Minified React error #31; visit https://react.dev/errors/31 for the full message
A production React build threw an error whose message was shortened to a number.
[vite] Internal server error: Failed to resolve import "x" from "src/App.jsx". Does the file exist?
Vite couldn’t find an imported file or package.
Two steps away (34)
RuntimeError: Working outside of application context.
Code used current_app, g, or a Flask extension (like SQLAlchemy) without an active Flask application context.
Adjacent JSX elements must be wrapped in an enclosing tag. Did you want a JSX fragment <>...</>?
A component returns two sibling JSX elements without a single parent.
Warning: Cannot update a component (`Parent`) while rendering a different component (`Child`)
A child component updated a parent’s state during its render instead of in an effect or event handler.
Error [ERR_REQUIRE_ESM]: require() of ES Module not supported
CommonJS code used `require()` on a package that is ES-module-only (node-fetch 3, chalk 5, nanoid 4, got 12…).
SyntaxError: Cannot use import statement outside a module
An `import` statement ran in a context treated as CommonJS (Node without "type": "module", a browser script without type="module"…
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"
Node tried to run a TypeScript file as ESM without a TypeScript loader.
Error: connect ECONNREFUSED 127.0.0.1:5432
Nothing is listening at that host:port — the target service is down or you’re connecting to the wrong address.
TypeError: Failed to fetch / NetworkError when attempting to fetch resource
The browser couldn’t complete the request at the network level — CORS, DNS, offline, blocked mixed content, or the server refused…
RuntimeError: Event loop is closed
Async code tried to use an event loop that has already been shut down.
Warning: A component is changing an uncontrolled input to be controlled
An input’s `value` started as `undefined` (uncontrolled) and later became a defined value (controlled), or vice versa.
TypeError: Cannot destructure property 'user' of 'useContext(...)' as it is undefined.
A component read a context with no matching Provider above it.
IndentationError: unexpected indent / expected an indented block
Python’s block structure is broken — inconsistent indentation or mixed tabs and spaces.
SyntaxError: Unexpected token '<' (HTML served instead of JavaScript)
The browser loaded a .js file but received HTML (an error page or the SPA index.html).
SyntaxError: Unexpected end of input
The parser reached the end of the code (or JSON) while still expecting more — a missing } ) ] or empty JSON.
TypeError: Reduce of empty array with no initial value
Array.reduce() ran on an empty array without an initial value.
RangeError: Invalid array length
An array was created or resized with a negative, fractional or enormous length.
URIError: URI malformed
decodeURIComponent/decodeURI received an invalid percent-encoded sequence.
java.net.SocketException: Connection reset
The remote side closed the TCP connection abruptly while Java was reading or writing.
DOMException: Failed to execute 'querySelector' on 'Document': 'x' is not a valid selector
The CSS selector string is invalid — often an ID starting with a digit or containing special characters.
SecurityError: Blocked a frame with origin "x" from accessing a cross-origin frame.
Script tried to read or modify an iframe (or window) from another origin.
error: externally-managed-environment
Your system Python (Debian 12+, Ubuntu 23.04+, Homebrew) refuses pip installs into the OS-managed environment (PEP 668).
Python was not found; run without arguments to install from the Microsoft Store
Windows ran the Microsoft Store “App execution alias” instead of a real Python installation.
SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame
pandas can’t tell whether your assignment modifies the original DataFrame or a temporary copy.
Error: Hydration failed because the initial UI does not match what was rendered on the server
The HTML rendered on the server differs from the first client render, so React (Next.js/Remix) can’t attach to it.
Warning: useLayoutEffect does nothing on the server
A component using useLayoutEffect was server-rendered, where layout effects can’t run.
Warning: Prop `className` did not match. Server: "x" Client: "y"
A prop rendered on the server differs from the client — usually CSS-in-JS class names or random IDs.
error: cannot lock ref 'refs/remotes/origin/x': is at … but expected … / unable to update local ref
Git couldn’t update a reference — stale remote-tracking refs, case-only branch name clashes, or a leftover lock file.
warning: ignoring broken ref refs/remotes/origin/HEAD
A ref file is empty or points to a missing object — usually refs/remotes/origin/HEAD after the default branch changed.
Warning: componentWillMount has been renamed, and is not recommended for use.
A class component uses legacy lifecycle methods (componentWillMount/WillReceiveProps/WillUpdate).
Error: Objects are not valid as a React child
You tried to render a plain object (or a Promise/Date) directly in JSX; React can only render strings, numbers, elements and arra…
Error: A cross-origin error was thrown. React doesn't have access to the actual error object in development.
An error happened in a script loaded from another origin, so the browser hid the details from React.
Error: Cannot find module 'x' (MODULE_NOT_FOUND)
Node can’t resolve the module path — the package isn’t installed, or a relative path/extension is wrong.
TS2307: Cannot find module 'x' or its corresponding type declarations.
TypeScript can’t resolve the import — the package isn’t installed, the path alias isn’t configured, or there are no types.
[vite] hmr invalidate … Could not Fast Refresh. Export is incompatible.
Fast Refresh fell back to a full reload because the file exports non-components alongside components.
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