ts-r
  • Error
  • Reported by the type checker

TS2515

Non-abstract class '{0}' does not implement inherited abstract member {1} from class '{2}'.

A concrete class extends an abstract class but doesn't implement one of its abstract members. Implement the member, or make the class abstract too.

What it means

Every abstract member of a base class must be implemented by the first non-abstract class that extends it. The class name is reported with the missing member and the class that declares it.

Example

index.ts
abstract class Shape {
  abstract area(): number;
}
export class Circle extends Shape {}
ts-r-check -p tsconfig.json --pretty false ts-r output
index.ts(4,14): error TS2515: Non-abstract class 'Circle' does not implement inherited abstract member area from class 'Shape'.

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

  • Implement the member in the class (here an area() method).
  • Or mark the class abstract and implement it in a further subclass.