ts-r
  • Error
  • Reported by the type checker

TS1253

Abstract properties can only appear within an abstract class.

An abstract property is declared in a class that isn't abstract. Mark the class `abstract`, or give the property a value.

What it means

Like abstract methods, abstract properties are only allowed in an abstract class, since something must subclass it and provide the value.

Example

index.ts
export class Config {
  abstract name: string;
}
ts-r-check -p tsconfig.json --pretty false ts-r output
index.ts(2,3): error TS1253: Abstract properties can only appear within an abstract class.

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

  • Mark the class abstract.
  • Or remove abstract and initialise the property.