getNodeIDByKey(key) {
		if (this.cache) {
			const cached = this.cache.get(key);
			if (cached) return cached;
		}

		const hashNum = this.getHash(key.toString());

		let found;
		const ringLen = this.ring.length;
		for (let i = 0; i < ringLen; i++) {
			if (hashNum <= this.ring[i].key) {
				found = this.ring[i];
				break;
			}
		}

		if (found) {
			if (this.cache) this.cache.set(key, found.nodeID);
			return found.nodeID;
		}
		return null;
	}
Get nodeID by a hashed numeric key.

@param {Number} key
@returns {String}
@memberof ShardStrategy