BUG: getters, setters and inheritance #13432
Description
TypeScript Version: 2.1.4
Code
class Base {
_height: number;
public set height (value: number) {
this._height = value;
}
}
class Intermediary extends Base {
public get height () {
return this._height;
}
}
class Concrete extends Intermediary {
constructor () {
super();
this.height = 10;
}
}
let c = new Concrete();
console.log(c.height);Expected behavior:
Should output 10.
Actual behavior:
- TypeScript error:
"Cannot assign to 'height' because it is a constant or a read-only property." - Generated JavaScript file outputs
undefined.
The problem here is that the Intermediary class is overwriting the set method. I've changed the output .js file to fix this issue, and it looked like this: (using getOwnPropertyDescriptor on parent's prototype to keep the set reference.)
var Intermediary = (function (_super) {
__extends(Intermediary, _super);
function Intermediary() {
return _super.apply(this, arguments) || this;
}
Object.defineProperty(Intermediary.prototype, "height", {
set: Object.getOwnPropertyDescriptor(_super.prototype, "height").set,
get: function () {
return this._height;
},
enumerable: true,
configurable: true
});
return Intermediary;
}(Base));