TypeScript TV

TS1175

'implements' clause already seen.

Broken Code ❌

interface Calculator {
  (x: number, y: number): number;
}
 
interface ExtendedCalculator extends Calculator {
  squareRoot(x: number): number;
}
 
class AdvancedCalculator implements ExtendedCalculator implements Calculator {
  // class implementation
}

Solution:

Remove the redundant implements Calculator since ExtendedCalculator already extends Calculator.

Fixed Code ✔️

interface Calculator {
  (x: number, y: number): number;
}
 
interface ExtendedCalculator extends Calculator {
  squareRoot(x: number): number;
}
 
class AdvancedCalculator implements ExtendedCalculator {
  // class implementation
}