tablesorter/js/widgets/widget-storage.js

/*! Widget: storage - updated 3/26/2015 (v2.21.3) */
/*global JSON:false */
;(function ($, window, document) {
	'use strict';

	var ts = $.tablesorter || {};
	// *** Store data in local storage, with a cookie fallback ***
	/* IE7 needs JSON library for JSON.stringify - (http://caniuse.com/#search=json)
	   if you need it, then include https://github.com/douglascrockford/JSON-js

	   $.parseJSON is not available is jQuery versions older than 1.4.1, using older
	   versions will only allow storing information for one page at a time

	   // *** Save data (JSON format only) ***
	   // val must be valid JSON... use http://jsonlint.com/ to ensure it is valid
	   var val = { "mywidget" : "data1" }; // valid JSON uses double quotes
	   // $.tablesorter.storage(table, key, val);
	   $.tablesorter.storage(table, 'tablesorter-mywidget', val);

	   // *** Get data: $.tablesorter.storage(table, key); ***
	   v = $.tablesorter.storage(table, 'tablesorter-mywidget');
	   // val may be empty, so also check for your data
	   val = (v && v.hasOwnProperty('mywidget')) ? v.mywidget : '';
	   alert(val); // 'data1' if saved, or '' if not
	*/
	ts.storage = function(table, key, value, options) {
		table = $(table)[0];
		var cookieIndex, cookies, date,
			hasStorage = false,
			values = {},
			c = table.config,
			wo = c && c.widgetOptions,
			storageType = ( options && options.useSessionStorage ) || ( wo && wo.storage_useSessionStorage ) ?
				'sessionStorage' : 'localStorage',
			$table = $(table),
			// id from (1) options ID, (2) table 'data-table-group' attribute, (3) widgetOptions.storage_tableId,
			// (4) table ID, then (5) table index
			id = options && options.id ||
				$table.attr( options && options.group || wo && wo.storage_group || 'data-table-group') ||
				wo && wo.storage_tableId || table.id || $('.tablesorter').index( $table ),
			// url from (1) options url, (2) table 'data-table-page' attribute, (3) widgetOptions.storage_fixedUrl,
			// (4) table.config.fixedUrl (deprecated), then (5) window location path
			url = options && options.url ||
				$table.attr(options && options.page || wo && wo.storage_page || 'data-table-page') ||
				wo && wo.storage_fixedUrl || c && c.fixedUrl || window.location.pathname;
		// https://gist.github.com/paulirish/5558557
		if (storageType in window) {
			try {
				window[storageType].setItem('_tmptest', 'temp');
				hasStorage = true;
				window[storageType].removeItem('_tmptest');
			} catch (error) {
				if (c && c.debug) {
					console.warn( storageType + ' is not supported in this browser' );
				}
			}
		}
		// *** get value ***
		if ($.parseJSON) {
			if (hasStorage) {
				values = $.parseJSON( window[storageType][key] || 'null' ) || {};
			} else {
				// old browser, using cookies
				cookies = document.cookie.split(/[;\s|=]/);
				// add one to get from the key to the value
				cookieIndex = $.inArray(key, cookies) + 1;
				values = (cookieIndex !== 0) ? $.parseJSON(cookies[cookieIndex] || 'null') || {} : {};
			}
		}
		// allow value to be an empty string too
		if ((value || value === '') && window.JSON && JSON.hasOwnProperty('stringify')) {
			// add unique identifiers = url pathname > table ID/index on page > data
			if (!values[url]) {
				values[url] = {};
			}
			values[url][id] = value;
			// *** set value ***
			if (hasStorage) {
				window[storageType][key] = JSON.stringify(values);
			} else {
				date = new Date();
				date.setTime(date.getTime() + (31536e+6)); // 365 days
				document.cookie = key + '=' + (JSON.stringify(values)).replace(/\"/g, '\"') + '; expires=' + date.toGMTString() + '; path=/';
			}
		} else {
			return values && values[url] ? values[url][id] : '';
		}
	};

})(jQuery, window, document);