Error map
await outside async SyntaxError: await is only valid in async functions and the top level bodies of modules
JavaScript · 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)
SyntaxError: invalid syntax
Python couldn’t parse the code. The caret (^) points at or just after the mistake.
Warning: An update to Component inside a test was not wrapped in act(...)
A component updated state after the test’s synchronous assertions — async work wasn’t awaited.
Dockerfile parse error line N: unknown instruction
A line in the Dockerfile doesn’t start with a valid instruction — usually a broken line continuation or a typo.
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.
SyntaxError: Unexpected end of input
The parser reached the end of the code (or JSON) while still expecting more — a missing } ) ] or empty JSON.
SyntaxError: Invalid regular expression: /x/: Unterminated group
A regex pattern has invalid syntax — unbalanced parentheses/brackets or unescaped special characters.
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 identifier
The parser found a name where it expected punctuation — usually a missing comma, operator or quote.
SyntaxError: Invalid or unexpected token
The code contains a character the parser can’t handle — smart quotes, stray characters or an unterminated string.
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.
Two steps away (30)
PHP Parse error: syntax error, unexpected …
PHP can’t parse the file because of a syntax mistake — the real error is often on the line before the one reported.
IndentationError: unexpected indent / expected an indented block
Python’s block structure is broken — inconsistent indentation or mixed tabs and spaces.
SyntaxError: missing ) after argument list
A function call’s parentheses are unbalanced — often an unescaped quote or a missing comma/plus.
RuntimeError: Event loop is closed
Async code tried to use an event loop that has already been shut down.
Warning: validateDOMNesting(...): <div> cannot appear as a descendant of <p>.
The JSX produces invalid HTML nesting, which also causes hydration mismatches in SSR.
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.
npm ERR! code ELIFECYCLE / Command failed with exit code 1
An npm script (build, start, test, postinstall) exited with an error. ELIFECYCLE is only the wrapper — the real error is printed…
gyp ERR! build error / node-gyp rebuild failed
A dependency with native C/C++ code couldn’t compile — missing build tools, Python, or an unsupported Node version.
COPY failed: file not found in build context / "/app/x": not found
The Dockerfile COPY refers to a path outside the build context, excluded by .dockerignore, or relative to the wrong directory.
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…
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: Unexpected token < in JSON at position 0
`JSON.parse()` / `response.json()` received something that isn’t JSON — very often an HTML error page.
com.fasterxml.jackson.databind.exc.MismatchedInputException: Cannot deserialize value of type `java.util.ArrayList` from Object value
Jackson found JSON whose shape doesn’t match the target Java type (object vs array, string vs number, missing constructor).
com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field "x", not marked as ignorable
The JSON contains a field your Java class doesn’t have, and Jackson is configured to fail on unknown properties.
SyntaxError: Identifier 'x' has already been declared
The same let/const/class name was declared twice in the same scope.
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.
GraphQL: Syntax Error: Expected Name, found <EOF> / Unexpected }
The GraphQL document is malformed — unbalanced braces, a stray comma/character, or an empty query.
Refused to execute script from 'x' because its MIME type ('text/html') is not executable
The browser fetched a script but the server labelled it text/html (usually an error page), so it refused to run it.
ChunkLoadError: Loading chunk 123 failed.
A lazily loaded JavaScript chunk couldn’t be downloaded — usually because a new deployment removed the old hashed files.
Failed to load module script: Expected a JavaScript module script but the server responded with a MIME type of "text/html"
A or dynamic import got HTML back instead of JavaScript.
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.
RuntimeError: Working outside of application context.
Code used current_app, g, or a Flask extension (like SQLAlchemy) without an active Flask application context.
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