deepool/src/deePool.js

deePool: highly-efficient pool for objects

"use strict";

const EMPTY_SLOT = Object.freeze(Object.create(null));


module.exports = { create };
module.exports.create = create;


// ******************************

// create a new pool
function create(objectFactory = ()=>({})) {
	var objPool = [];
	var nextFreeSlot = null;	// pool location to look for a free object to use

	return {
		use,
		recycle,
		grow,
		size,
	};


	// ******************************

	function use() {
		if (nextFreeSlot == null || nextFreeSlot == objPool.length) {
			grow( objPool.length || 5 );
		}

		var objToUse = objPool[nextFreeSlot];
		objPool[nextFreeSlot++] = EMPTY_SLOT;
		return objToUse;
	}

	function recycle(obj) {
		if (nextFreeSlot == null || nextFreeSlot == -1) {
			objPool[objPool.length] = obj;
		}
		else {
			objPool[--nextFreeSlot] = obj;
		}
	}

	function grow(count = objPool.length) {
		if (count > 0 && nextFreeSlot == null) {
			nextFreeSlot = 0;
		}

		if (count > 0) {
			var curLen = objPool.length;
			objPool.length += Number(count);

			for (var i = curLen; i < objPool.length; i++) {
				// add new obj to pool
				objPool[i] = objectFactory();
			}
		}

		return objPool.length;
	}

	function size() {
		return objPool.length;
	}
}