ts-r
  • Error
  • Reported by the type checker

TS2503

Cannot find namespace '{0}'.

A qualified type name like A.B refers to a namespace that doesn't exist. Import the namespace or fix its name.

What it means

In a type position, Name.Member looks Name up as a namespace. When no namespace (or namespace import, or enum) with that name is in scope, it is reported. Missing @types packages that provide global namespaces such as NodeJS or React are a common cause.

Example

index.ts
export let timer: Timers.Handle;
ts-r-check -p tsconfig.json --pretty false ts-r output
index.ts(1,19): error TS2503: Cannot find namespace 'Timers'.

Recorded by node scripts/verify-examples.mjs with ts-r built from commit 6deaf01. The example uses the default tsconfig: strict, target: es2022, module: esnext, moduleResolution: bundler.

How to fix

  • Fix the spelling, or import the namespace: import type * as Timers from "./timers".
  • For global namespaces from type packages, install the package and add it to types in tsconfig if you list them.