Error map

req.body undefined Express: req.body is undefined / {} (body parser missing)

Node.js · layer 4, Application & API

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Centre: this error. First ring: errors it is linked with (8). 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.

1 · On your device 2 · Network 4 · Application & API 5 · Data 7 · Build & delivery
req.body undefined — Express: req.body is undefined / {} (body parser missing) (Node.js)req.body un…MODULE_NOT_FOUND — Error: Cannot find module 'x' (MODULE_NOT_FOUND) (Node.js)MODULE_NOT_FOUNDMongoose ValidationError — ValidationError: User validation failed: email: Path `email` is required. (Node.js)Mongoose Validation…SyntaxError import — SyntaxError: Cannot use import statement outside a module (Node.js)SyntaxError importDEP0005 — DeprecationWarning: Buffer() is deprecated due to security and usability issues (DEP0005) (Node.js)DEP0005path-to-regexp — TypeError: Missing parameter name at 1 (path-to-regexp) (Node.js)path-to-regexpERR_HTTP_HEADERS_SENT — Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client (Node.js)ERR_HTTP_HEADERS_SE…DEP0040 — DeprecationWarning: The `punycode` module is deprecated (DEP0040) (Node.js)DEP0040Router.use middleware — TypeError: Router.use() requires a middleware function but got a Object (Node.js)Router.use middlewa…ERESOLVE — npm ERR! code ERESOLVE — unable to resolve dependency tree (npm)ERESOLVEENOENT — Error: ENOENT: no such file or directory (Node.js)ENOENTTypeError: not a function — TypeError: x is not a function (JavaScript)TypeError: not a fu…422 — HTTP 422 Unprocessable Content (HTTP)422IllegalArgumentException — java.lang.IllegalArgumentException (Java)IllegalArgumentExce…buffering timed out — MongooseError: Operation `users.find()` buffering timed out after 10000ms (Node.js)buffering timed outReferenceError — ReferenceError: x is not defined (JavaScript)ReferenceErrorERR_REQUIRE_ESM — Error [ERR_REQUIRE_ESM]: require() of ES Module not supported (Node.js)ERR_REQUIRE_ESMERR_UNKNOWN_FILE_EXTENSION — TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts" (Node.js)ERR_UNKNOWN_FILE_EX…ERR_IMPORT_ATTRIBUTE_MISSING — TypeError [ERR_IMPORT_ATTRIBUTE_MISSING]: Module needs an import attribute of "type: json" (Node.js)ERR_IMPORT_ATTRIBUT…Unhandled 'error' event — Error: Unhandled 'error' event (events.js / node:events) (Node.js)Unhandled 'error' e…EBADENGINE — npm WARN EBADENGINE Unsupported engine / The engine "node" is incompatible with this module (Node.js)EBADENGINE404 — HTTP 404 Not Found (HTTP)404405 — HTTP 405 Method Not Allowed (HTTP)405Whitelabel Error Page — Whitelabel Error Page — This application has no explicit mapping for /error (Java)Whitelabel Error Pa…Headers already sent — Warning: Cannot modify header information - headers already sent (PHP)Headers already sentCould not resolve — Gradle: Could not resolve all files for configuration / Could not resolve dependency (Android)Could not resolveClassNotFoundException — java.lang.ClassNotFoundException / NoClassDefFoundError (Java)ClassNotFoundExcept…CocoaPods compatible versions — CocoaPods could not find compatible versions for pod (iOS)CocoaPods compatibl…not a constructor — TypeError: x is not a constructor (JavaScript)not a constructorTDZ — ReferenceError: Cannot access 'x' before initialization (JavaScript)TDZ1046 — MySQL ERROR 1046 (3D000): No database selected (MySQL)1046

Directly related (8)

MODULE_NOT_FOUNDNode.js

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.

Mongoose ValidationErrorNode.js

ValidationError: User validation failed: email: Path `email` is required.

A document failed Mongoose schema validation before saving.

SyntaxError importNode.js

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"…

DEP0005Node.js

DeprecationWarning: Buffer() is deprecated due to security and usability issues (DEP0005)

Code (yours or a dependency) uses the deprecated new Buffer() constructor.

path-to-regexpNode.js

TypeError: Missing parameter name at 1 (path-to-regexp)

An Express 5 (path-to-regexp v8) route uses old wildcard syntax like '*' or '/:id?'.

ERR_HTTP_HEADERS_SENTNode.js

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.

DEP0040Node.js

DeprecationWarning: The `punycode` module is deprecated (DEP0040)

A dependency imports Node’s built-in punycode module, deprecated since Node 21.

Router.use middlewareNode.js

TypeError: Router.use() requires a middleware function but got a Object

app.use()/router.use() received an object instead of a function — usually a router module that wasn’t exported.

Two steps away (22)

ERESOLVEnpm

npm ERR! code ERESOLVE — unable to resolve dependency tree

npm 7+ found conflicting peer dependency requirements and refuses to install a broken tree.

ENOENTNode.js

Error: ENOENT: no such file or directory

A file or directory the program tried to open doesn’t exist at that path.

TypeError: not a functionJavaScript

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…).

422HTTP

HTTP 422 Unprocessable Content

The request is well-formed, but the data fails validation (e.g. invalid email, missing required field).

IllegalArgumentExceptionJava

java.lang.IllegalArgumentException

A method rejected an argument value as invalid.

buffering timed outNode.js

MongooseError: Operation `users.find()` buffering timed out after 10000ms

Mongoose queued a query waiting for a connection that never opened.

ReferenceErrorJavaScript

ReferenceError: x is not defined

Code refers to a variable or function name that doesn’t exist in the current scope.

ERR_REQUIRE_ESMNode.js

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…).

ERR_UNKNOWN_FILE_EXTENSIONNode.js

TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"

Node tried to run a TypeScript file as ESM without a TypeScript loader.

ERR_IMPORT_ATTRIBUTE_MISSINGNode.js

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.

Unhandled 'error' eventNode.js

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.

EBADENGINENode.js

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.

404HTTP

HTTP 404 Not Found

The server can’t find anything at the requested URL.

405HTTP

HTTP 405 Method Not Allowed

The URL exists, but it doesn’t accept the HTTP method you used (e.g. POST to a GET-only route).

Whitelabel Error PageJava

Whitelabel Error Page — This application has no explicit mapping for /error

Spring Boot’s default error page — the request hit no controller mapping (404) or a controller threw (500).

Headers already sentPHP

Warning: Cannot modify header information - headers already sent

You called `header()`, `setcookie()` or `session_start()` after output had already been sent to the browser.

Could not resolveAndroid

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.

ClassNotFoundExceptionJava

java.lang.ClassNotFoundException / NoClassDefFoundError

The JVM couldn’t find a class on the classpath at runtime.

CocoaPods compatible versionsiOS

CocoaPods could not find compatible versions for pod

pod install can’t satisfy the version constraints — outdated spec repo, a higher deployment target required, or two pods needing…

not a constructorJavaScript

TypeError: x is not a constructor

new was used with something that isn’t a class/constructor — usually a wrong import.

TDZJavaScript

ReferenceError: Cannot access 'x' before initialization

A let/const/class was used before its declaration line ran (temporal dead zone) — often a circular import.

1046MySQL

MySQL ERROR 1046 (3D000): No database selected

A query referenced tables without a database selected (no USE and no db in the connection).

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