Today I encountered an error learning TypeScript polymorphism (i.e., inheritance)
Mistakes show

here indicates an error with super inheritance. String arguments cannot be assigned to string arguments. What the hell is this
To solve the error
See String, think of it, change to String try it? So he can
Modified polymorphic code

class Animal {
    name:String
    constructor(name:String) {
        this.name = name
    }
    eat() {}
}
class Dog extends Animal{
    constructor(name:String) {
        super(name)
    }
    eat() {
        return this.name + 'Eat Bean'
    }
}
class Cat extends Animal{
    constructor(name:String) {
        super(name)
    }
    eat() {
        return this.name + 'Eat?'
    }
}
let dog = new Dog('WW')
console.log(dog.eat())
let cat = new Cat('MM')
console.log(cat.eat())

Questions remain
In fact, the previous use of string inheritance is shown without error information, I don’t know why there is an error when using polymorphic inheritance, so I can only change it to string according to the prompt. If you know the reason, please give instruction