Error map
MODULE_NOT_FOUND Error: Cannot find module 'x' (MODULE_NOT_FOUND)
Node.js · layer 4, Application & API
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)
ModuleNotFoundError: No module named 'x'
Python can’t find the module you import — it isn’t installed in the interpreter/virtualenv that’s running, or the import path is…
[nodemon] app crashed - waiting for file changes before starting...
Your app threw an error on startup; nodemon is waiting for a file change to retry.
Error: ENOENT: no such file or directory
A file or directory the program tried to open doesn’t exist at that path.
npm ERR! code ERESOLVE — unable to resolve dependency tree
npm 7+ found conflicting peer dependency requirements and refuses to install a broken tree.
npm WARN EBADENGINE Unsupported engine / The engine "node" is incompatible with this module
A package requires a different Node.js version than the one you’re running.
TypeError: x is not a function
You called something as a function, but its value is not a function (it’s undefined, a string, an object…).
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"…
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…).
Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './x' is not defined by "exports"
You imported a deep path inside a package that its package.json "exports" field doesn’t expose.
Error: Unhandled 'error' event (events.js / node:events)
An EventEmitter (stream, socket, child process, server) emitted 'error' and nothing listened for it, so Node crashed.
WRONGTYPE Operation against a key holding the wrong kind of value
A Redis command was used on a key of a different type (e.g. HGET on a string key).
Error: Node Sass does not yet support your current environment
node-sass (deprecated) has no binary for your Node version/OS.
Two steps away (33)
PHP Fatal error: Uncaught Error: Class "X" not found
PHP couldn’t load the class — autoloading failed, the namespace is wrong, or the dependency isn’t installed.
ImportError: cannot import name 'x' from 'y'
The module was found, but the name you’re importing from it doesn’t exist — usually a version change or a circular import.
NameError: name 'x' is not defined
Python doesn’t know the name — it was never assigned/imported in this scope, or it’s misspelled.
Error: listen EADDRINUSE: address already in use :::3000
Another process is already listening on that port.
HTTP Error 500.30 - ASP.NET Core app failed to start
IIS/Azure’s ASP.NET Core Module launched your app but it crashed during startup.
java.lang.ExceptionInInitializerError
A static initializer (static block or static field) threw an exception while the class was loading.
bash: command not found
The shell can’t find an executable with that name in any directory on your PATH.
Windows Error 0x80070002: The system cannot find the file specified
A file or registry entry Windows expected is missing — common in Windows Update, backups and app installs.
Too many open files (EMFILE)
The process hit its file-descriptor limit — sockets, files and pipes all count.
npm ERR! code EACCES — permission denied
npm can’t write to a directory — usually global installs into a root-owned folder.
npm ERR! code E404 — 404 Not Found: package@version is not in this registry
npm asked the registry for a package (or version) that doesn’t exist there — a typo, a private/scoped package without auth, or th…
npm ERR! code EINTEGRITY — sha512 integrity checksum failed
A downloaded package’s hash doesn’t match the integrity value in package-lock.json — a corrupted cache, a changed tarball, or a l…
Gradle: Could not resolve all files for configuration / Could not resolve dependency
Gradle couldn’t download a dependency — wrong coordinates/version, missing repository, offline mode, or network/proxy issues.
Duplicate class X found in modules A and B
Two dependencies ship the same class — typically old Android Support libraries mixed with AndroidX, or Kotlin stdlib-jdk7/jdk8 ve…
DeprecationWarning: Buffer() is deprecated due to security and usability issues (DEP0005)
Code (yours or a dependency) uses the deprecated new Buffer() constructor.
TypeError: Cannot read properties of undefined (reading 'x')
You tried to access a property on a value that is `undefined` (or `null`) — usually data that hasn’t loaded yet or a wrong proper…
ReferenceError: x is not defined
Code refers to a variable or function name that doesn’t exist in the current scope.
AttributeError: 'X' object has no attribute 'y'
You accessed an attribute or method that doesn’t exist on that object type.
Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
An Express/Node handler tried to send a second response (or set headers) after one was already sent.
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"
Node tried to run a TypeScript file as ESM without a TypeScript loader.
TypeError [ERR_IMPORT_ATTRIBUTE_MISSING]: Module needs an import attribute of "type: json"
An ES module imported a .json file without the required import attribute.
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.
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.
DeprecationWarning: The `punycode` module is deprecated (DEP0040)
A dependency imports Node’s built-in punycode module, deprecated since Node 21.
Runtime.ImportModuleError: Unable to import module 'lambda_function': No module named 'x'
Lambda couldn’t load your handler file or one of its dependencies — the package is missing from the deployment zip/layer or the h…
Unmet dependencies / E: Unable to correct problems, you have held broken packages
apt can’t find a set of package versions that satisfies all dependencies — usually mixed repositories or a package from another r…
Error: listen EACCES: permission denied 0.0.0.0:80
Node isn’t allowed to bind that port — ports below 1024 need root on Linux/macOS, and some Windows ports are reserved.
MaxListenersExceededWarning: Possible EventEmitter memory leak detected. 11 listeners added
More than 10 listeners were added to one event — often a leak where listeners are added repeatedly.
ReplyError: NOAUTH Authentication required.
The Redis server requires a password (or ACL user) but the client didn’t authenticate.
WordPress: Error establishing a Redis connection (object cache)
The persistent object cache drop-in (object-cache.php) can’t connect to Redis, so the whole site fails.
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: error:0308010C:digital envelope routines::unsupported
An old build tool (webpack 4, old react-scripts) uses a hash algorithm that OpenSSL 3 in Node 17+ disables.
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