class A
{
protected _value:number;
get value()
{
return this._value;
}
}
class B extends A
{
set value(v:number)
{
this._value = v;
}
}
var b = new B();
b.value = 2;
console.log(b.value);//undefined
If a subclass defines only a setter, it won't be able to access the value.
I believe that using Object.defineProperty to set "value" on B.prototype could potentially override the getter and setter on A.prototype.
There has been a lengthy discussion regarding the restriction on accessors in this particular thread.
To achieve the desired behavior, you can either include both getter and setter in the superclass:
class A
{
protected _value:number;
get value():number
{
return this._value;
}
set value(v:number)
{
this._value = v;
}
}
class B extends A
{
}
Alternatively, you can override both in the subclass:
class A
{
protected _value:number;
get value():number
{
return this._value;
}
set value(v:number)
{
this._value = v;
}
}
class B extends A
{
get value():number
{
return this._value;
}
set value(v:number)
{
this._value = v;
}
}
If you choose not to use accessors but opt for normal methods instead, the behavior is as expected:
class A
{
protected _value:number;
getvalue():number
{
return this._value;
}
}
class B extends A
{
setvalue(v:number)
{
this._value = v;
}
}
const b:B = new B();
b.setvalue(2);
console.log(b.getvalue());
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