Error map
TS2693: 'X' only refers to a type, but is being used as a value here TypeScript: error TS2693: 'User' only refers to a type, but is being used as a value here.
TypeScript · layer 1, On your device
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.
Directly related (8)
TS2304: Cannot find name 'x'.
TypeScript doesn’t know an identifier — a missing import, missing type definitions (e.g. for Node or Jest globals), or a typo.
TypeScript: error TS1208: 'index.ts' cannot be compiled under '--isolatedModules' because it is considered a global script file. Add an import, export, or an empty 'export {}' statement
With `isolatedModules`, every file must be a module (have an import or export).
TypeScript: error TS2349: This expression is not callable. Type 'X' has no call signatures.
You called something TypeScript believes isn't a function (a union without compatible signatures, a module namespace, an object).
TypeScript: error TS1192: Module '"./utils"' has no default export.
You used `import x from "./mod"` but the module only has named exports.
TypeScript: error TS1484: 'User' is a type and must be imported using a type-only import when 'verbatimModuleSyntax' is enabled.
With `verbatimModuleSyntax` or `isolatedModules`, types must be imported/re-exported with `import type` / `export type`.
TypeScript: error TS1005: ';' expected.
The parser hit a syntax error — missing punctuation, mismatched brackets, or an unsupported syntax for your TypeScript version.
TypeScript: error TS1128: Declaration or statement expected.
The parser found a token where a declaration or statement should start — usually stray braces/parentheses or code outside a funct…
TypeScript: error TS2307: Cannot find module './App.vue' or its corresponding type declarations.
TypeScript doesn't know what a `.vue` import is without a shim or Volar/`vue-tsc`.
Two steps away (24)
ReferenceError: x is not defined
Code refers to a variable or function name that doesn’t exist in the current scope.
java.lang.ClassCastException: class A cannot be cast to class B
An object was cast to a type it isn’t.
TypeError [ERR_INVALID_ARG_TYPE]: The "path" argument must be of type string. Received undefined
A Node API got an argument of the wrong type — usually undefined because an env var or config value is missing.
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_IMPORT_ATTRIBUTE_MISSING]: Module needs an import attribute of "type: json"
An ES module imported a .json file without the required import attribute.
TypeScript: error TS2366: Function lacks ending return statement and return type does not include 'undefined'.
A function with a declared return type can reach its end without returning on some path.
TypeScript: error TS2393: Duplicate function implementation.
A function with the same name/signature is implemented more than once in the same scope.
TypeScript: error TS2554: Expected 2 arguments, but got 1.
A call passes too few or too many arguments.
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…).
TypeError: x is not a constructor
new was used with something that isn’t a class/constructor — usually a wrong import.
ReferenceError: Cannot access 'x' before initialization
A let/const/class was used before its declaration line ran (temporal dead zone) — often a circular import.
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.
Error: Element type is invalid: expected a string (for built-in components) or a class/function (for composite components) but got: undefined
JSX referenced a component that is undefined — almost always a default/named import mismatch.
Next.js: Module not found: Can't resolve '@/components/Button' / 'lodash' in '/app/src'
Webpack/Turbopack couldn't resolve an import — wrong path/alias, missing dependency or case mismatch.
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.
SyntaxError: missing ) after argument list
A function call’s parentheses are unbalanced — often an unescaped quote or a missing comma/plus.
SyntaxError: Identifier 'x' has already been declared
The same let/const/class name was declared twice in the same scope.
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).
SyntaxError: Unexpected identifier
The parser found a name where it expected punctuation — usually a missing comma, operator or quote.
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"
Node tried to run a TypeScript file as ESM without a TypeScript loader.
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.
TS7016: Could not find a declaration file for module 'x'. 'x.js' implicitly has an 'any' type.
The JavaScript package has no TypeScript types bundled and no @types package installed.
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