EC
TS2653
TypeScriptERRORNotableTypeHIGH confidence

Non-abstract class expression does not implement inherited abstract member 'X...

Production Risk

Build will fail; resolve before shipping.

What this means

A type-checking error (TS2653): Non-abstract class expression does not implement inherited abstract member 'X' from class 'X'.. This diagnostic is emitted by the TypeScript compiler when non-abstract class expression does not implement inherited abstract member 'X' from class 'X'..

Why it happens
  1. 1A concrete class extends an abstract class but does not implement all abstract members
How to reproduce

TypeScript compiler reports TS2653 during type checking.

trigger — this will error
trigger — this will error
// Triggers TS2653
// Non-abstract class expression does not implement inherited abstract member 'X' from class 'X'.

expected output

error TS2653: Non-abstract class expression does not implement inherited abstract member 'X' from class 'X'.

Fix

Implement all abstract members

WHEN Extending an abstract class

Implement all abstract members
abstract class Base {
  abstract doWork(): void;
}
class Derived extends Base {
  doWork(): void { /* implementation */ }
}

Why this works

All abstract members must be implemented in concrete subclasses.

Sources
Official documentation ↗

TypeScript Compiler Diagnostics

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