isEqualTo(obj) {
        if (!(obj instanceof Point)) {
            return false;
        }
        /** @type {!Point} */
        let other = obj;
        return other.x === this.x && other.y === this.y;
    }
Determines if the given value is a point with the same coordinates as the receiving point.
@param {!Point|*} obj The point, or other value, to compare against.
@returns {!boolean}