JuniorTheoryCommon

What does the program print?

JavaScript

class Rect {
    constructor(w, h) {
        this.w = w;
        this.h = h;
    }
    get area() {
        return this.w * this.h;
    }
}
const r = new Rect(2, 3);
r.w = 5;
console.log(r.area);

Expecting 6: a getter is not computed once when the object is created; it runs on every read, so r.area uses the new w — 5 * 3.
Expecting undefined because area is read without (): a get method runs on a plain property read, and r.area() would in fact stop the program with a TypeError.

What does the program print if r.w = 5; is moved below the console.log line?
What happens if the program calls r.area() with parentheses?

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JuniorTheoryCommon

What does the program print?

JavaScript

class Rect {
    constructor(w, h) {
        this.w = w;
        this.h = h;
    }
    get area() {
        return this.w * this.h;
    }
}
const r = new Rect(2, 3);
r.w = 5;
console.log(r.area);

Expecting 6: a getter is not computed once when the object is created; it runs on every read, so r.area uses the new w — 5 * 3.
Expecting undefined because area is read without (): a get method runs on a plain property read, and r.area() would in fact stop the program with a TypeError.

What does the program print if r.w = 5; is moved below the console.log line?
What happens if the program calls r.area() with parentheses?

Back to questions Open topic in roadmap →Answer it yourself — Quiz