SessionStorageによるローカルキャッシュ

LocalCache.js

var localCache = {
	get: function(key, getMethod, cacheMs) {
		if(!cacheMs) cacheMs = this._defaultCacheMs;
		
		var cache = sessionStorage.getItem(key);
		if(cache == null) {
			return this._setAndGet(key, getMethod, cacheMs);
		}
		
		var data = JSON.parse(cache);
		if(new Date() > new Date(data.expire)) {
			return this._setAndGet(key, getMethod, cacheMs);
		}
		
		return data.value;
	},
	_defaultCacheMs: 1000 * 60,
	_setAndGet: function(key, getMethod, cacheMs) {
		if(!getMethod)return null;
		
		sessionStorage.setItem(key, JSON.stringify({
			value :getMethod(),
			expire : new Date(new Date().getTime() + cacheMs).getTime(),
		}));
		return this.get(key);
	},
}