TS4114

error TS4114: This member must have an ‘override‘ modifier because it overrides a member in the base class ‘MyBaseClass‘.

Broken Code ❌

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class MyBaseClass {
  sayHello(): string {
    return 'Hello!';
  }
}

class MyDerivedClass extends MyBaseClass {
  sayHello(): string {
    return 'Welcome!';
  }
}

Fixed Code ✔️

The error pops up when “noImplicitOverride” is set to true in your “tsconfig.json” file, and you don’t use the override modifier when overwriting a function from your base class. You can fix this by setting “noImplicitOverride” to false (not recommended) or using the override modifier (preferred solution):

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class MyBaseClass {
  sayHello(): string {
    return 'Hello!';
  }
}

class MyDerivedClass extends MyBaseClass {
  override sayHello(): string {
    return 'Welcome!';
  }
}