Generic with interface class type

Question

Could anyone explain why do I get the following error?

Property 'prop1' does not exist on type 'A'.ts(2339)

The code

interface A {
  prop1:string;
};

class myClass<A> {
  ptop1: string;
  constructor(input: A) {
    this.ptop1 = input.prop1;  //error happens in this line (Property 'prop1' does not exist on type 'A'.ts(2339))
  }
}

Answer 1

You can do like this

interface A {
  prop1: string
}

// constraint A1 with A
class myClass <A1 extends A> {
  ptop1: string
  constructor(input: A1){
    this.ptop1 = input.prop1
  }
}

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