mywebsite/node_modules/memoizee/ext/ref-counter.js

// Reference counter, useful for garbage collector like functionality

'use strict';

var d          = require('d')
  , extensions = require('../lib/registered-extensions')

  , create = Object.create, defineProperties = Object.defineProperties;

extensions.refCounter = function (ignore, conf, options) {
	var cache, postfix;

	cache = create(null);
	postfix = (options.async && extensions.async) ? 'async' : '';

	conf.on('set' + postfix, function (id, length) { cache[id] = length || 1; });
	conf.on('get' + postfix, function (id) { ++cache[id]; });
	conf.on('delete' + postfix, function (id) { delete cache[id]; });
	conf.on('clear' + postfix, function () { cache = {}; });

	defineProperties(conf.memoized, {
		deleteRef: d(function () {
			var id = conf.get(arguments);
			if (id === null) return null;
			if (!cache[id]) return null;
			if (!--cache[id]) {
				conf.delete(id);
				return true;
			}
			return false;
		}),
		getRefCount: d(function () {
			var id = conf.get(arguments);
			if (id === null) return 0;
			if (!cache[id]) return 0;
			return cache[id];
		})
	});
};