Error map
TS2300: Duplicate identifier TypeScript: error TS2300: Duplicate identifier 'Foo'.
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 TS2451: Cannot redeclare block-scoped variable 'name'.
A `let`/`const`/`class` name was declared twice in the same scope — often because files are global scripts sharing one scope.
TypeScript: error TS2393: Duplicate function implementation.
A function with the same name/signature is implemented more than once in the same scope.
TypeScript: error TS2403: Subsequent variable declarations must have the same type. Variable 'x' must be of type 'string', but here has type 'number'.
A `var` was redeclared with a different type (or global declarations conflict).
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 TS4023: Exported variable 'x' has or is using name 'Foo' from external module "..." but cannot be named. / TS2742: The inferred type cannot be named without a reference
With `declaration: true`, TypeScript can't write the inferred type into `.d.ts` because it refers to a type it can't import by na…
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.
SyntaxError: Identifier 'x' has already been declared
The same let/const/class name was declared twice in the same scope.
ReferenceError: Cannot access 'x' before initialization
A let/const/class was used before its declaration line ran (temporal dead zone) — often a circular import.
TypeScript: error TS2305: Module '"./utils"' has no exported member 'helper'.
You imported a named export that the module doesn't 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 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 TS2554: Expected 2 arguments, but got 1.
A call passes too few or too many arguments.
TypeError: Assignment to constant variable.
Code reassigned a variable declared with const.
TS2322: Type 'X' is not assignable to type 'Y'
You assigned a value whose type doesn’t match the declared type of the variable, property or return value.
TypeScript: error TS1192: Module '"./utils"' has no default export.
You used `import x from "./mod"` but the module only has named exports.
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: 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.
SyntaxError: Invalid or unexpected token
The code contains a character the parser can’t handle — smart quotes, stray characters or an unterminated string.
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.
TypeScript: error TS7022: 'x' implicitly has type 'any' because it does not have a type annotation and is referenced directly or indirectly in its own initializer
A variable's inferred type depends on itself (circular inference).
TypeScript: error TS2589: Type instantiation is excessively deep and possibly infinite.
The compiler hit its recursion limit while evaluating a very complex or recursive generic type.
TypeError [ERR_UNKNOWN_FILE_EXTENSION]: Unknown file extension ".ts"
Node tried to run a TypeScript file as ESM without a TypeScript loader.
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.
TS2339: Property 'x' does not exist on type 'Y'.
TypeScript’s type for the object doesn’t include that property.
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