createIndexGetter = index => {
		/**
		 * @this {Set<T>} a Set
		 * @returns {T | undefined} the value at this location
		 */
		// eslint-disable-next-line func-style
		const fn = function () {
			dIndexer();
			let i = 0;
			for (const item of this) {
				if (i++ === index) return item;
			}
		};
		return fn;
	}
@param {number} index index
@returns {() => T | undefined} value