change lodash groupby key for undefined
This will do
const groupData = _.groupBy(itemData, item => { return _.get(item, 'category__article.name', 'no_category'); });Using _.get to fetch nested value (item.category__article.name) and give default value (no_category) if the value is undefined.
const itemData = { 0: { name: 'article 1', category_id : 1, category__article: { id: 1, name: 'news' } }, 1: { name: 'article 2', category_id : 2, category__article: { id: 2, name: 'lifestyle' } }, 2: { name: 'article 3', category_id : '', category__article: undefined }}const groupData = _.groupBy(itemData, item => _.get(item, 'category__article.name', 'no_category'));console.log('groupData', groupData);<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.5/lodash.js"></script>
Lodash groupBy method can accept a function as a parameter. So you can default the category value to 'other' as easy as this:
const itemData = { 0: { name: "article 1", category: "news" }, 1: { name: "article 2", category: undefined }, 2: { name: "article 3", category: null }};const groupkey = "category";const defaultCategory = "other";var value = _.groupBy(itemData, item => { const value = item[groupkey]; if (!value) { return defaultCategory; } return value;});/*Returns: { news: [{ name: "article 1", category: "news" }], other: [ { name: "article 2", category: undefined }, { name: "article 3", category: null } ]}*/
comparing the value directly, or (!t)
if (t === undefined) { return 'Undefined value!'; }https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/undefined