/**
* @file dom-data.js
* @module dom-data
*/
import * as Guid from './guid.js';
/**
* Element Data Store.
*
* Allows for binding data to an element without putting it directly on the
* element. Ex. Event listeners are stored here.
* (also from jsninja.com, slightly modified and updated for closure compiler)
*
* @type {Object}
* @private
*/
const elData = {};
/*
* Unique attribute name to store an element's guid in
*
* @type {String}
* @constant
* @private
*/
const elIdAttr = 'vdata' + (new Date()).getTime();
/**
* Returns the cache object where data for an element is stored
*
* @param {Element} el
* Element to store data for.
*
* @return {Object}
* The cache object for that el that was passed in.
*/
export function getData(el) {
let id = el[elIdAttr];
if (!id) {
id = el[elIdAttr] = Guid.newGUID();
}
if (!elData[id]) {
elData[id] = {};
}
return elData[id];
}
/**
* Returns whether or not an element has cached data
*
* @param {Element} el
* Check if this element has cached data.
*
* @return {boolean}
* - True if the DOM element has cached data.
* - False otherwise.
*/
export function hasData(el) {
const id = el[elIdAttr];
if (!id) {
return false;
}
return !!Object.getOwnPropertyNames(elData[id]).length;
}
/**
* Delete data for the element from the cache and the guid attr from getElementById
*
* @param {Element} el
* Remove cached data for this element.
*/
export function removeData(el) {
const id = el[elIdAttr];
if (!id) {
return;
}
// Remove all stored data
delete elData[id];
// Remove the elIdAttr property from the DOM node
try {
delete el[elIdAttr];
} catch (e) {
if (el.removeAttribute) {
el.removeAttribute(elIdAttr);
} else {
// IE doesn't appear to support removeAttribute on the document element
el[elIdAttr] = null;
}
}
}