randomIndex (compliments) {
		if (compliments.length <= 1) {
			return 0;
		}

		const generate = function () {
			return Math.floor(Math.random() * compliments.length);
		};

		let complimentIndex = generate();

		while (complimentIndex === this.lastComplimentIndex) {
			complimentIndex = generate();
		}

		this.lastComplimentIndex = complimentIndex;

		return complimentIndex;
	}
Generate a random index for a list of compliments.
@param {string[]} compliments Array with compliments.
@returns {number} a random index of given array