[英]How to groupby in lodash for each item in a nested array
我有一個形式的json數組:
[{
"published": true,
"tags": ["tag1", "tag2"],
"categories": ["cat1"],
"author": "some name",
"post-format": "standard",
"title": "Second Post,",
"url-slug": "second-post",
"first-published-on": "2019-03-28",
"last-updated-on": "2019-03-28",
"meta": {
"title": "Second Post",
"description": "Second post."
},
"excerpt": "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt",
"path": "2019/03/28/SecondPost.md"
}, {
"published": true,
"tags": ["tag1", "tag2", "tag3"],
"categories": ["cat1", "cat2"],
"author": "some name",
"post-format": "standard",
"title": "Getting Started",
"url-slug": "getting-started",
"first-published-on": "2019-03-20",
"last-updated-on": "2019-03-20",
"meta": {
"title": "Getting Started",
"description": "Getting started post."
},
"excerpt": "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt",
"path": "2019/03/20/GettingStarted.md"
}]
我想按標簽將它們分組,格式如下:
[{
"tag1": [{...}, {...}],
"tag2": [{...}, {...}],
"tag3": [{...}]
}]
我嘗試使用lodash這樣做:
const groupedByTag = _.groupBy(blogMetadata, function(postmetadata) {
postmetadata.tags.map(tag => {
return tag
})
})
顯然,以上代碼不正確,無法正常工作。 我看了一篇相關文章 ,但進展不大。 任何幫助表示贊賞。
這里的主意是
obj
變量的每個元素。 tags
屬性。 op
已經具有該標簽,然后我們推入該值,否則我們向具有相應值的op
對象添加一個新鍵 let obj = [{"published": true,"tags": ["tag1", "tag2"],"categories": ["cat1"],"author": "some name","post-format": "standard","title": "Second Post,","url-slug": "second-post","first-published-on": "2019-03-28","last-updated-on": "2019-03-28","meta": {"title": "Second Post","description": "Second post."},"excerpt": "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt","path": "2019/03/28/SecondPost.md"}, {"published": true,"tags": ["tag1", "tag2", "tag3"],"categories": ["cat1", "cat2"],"author": "some name","post-format": "standard","title": "Getting Started","url-slug": "getting-started","first-published-on": "2019-03-20","last-updated-on": "2019-03-20","meta": {"title": "Getting Started","description": "Getting started post."},"excerpt": "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt","path": "2019/03/20/GettingStarted.md"}] let final = obj.reduce((op,inp) => { inp.tags.forEach(e => { op[e] = op[e] || [] op[e].push(JSON.parse(JSON.stringify(inp))) }) return op },{}) console.log(final)
您可以使用reduce
& forEach
替代loadash
。 在reduce回調函數中,對tags
進行迭代,並檢查累加器對象是否存在該名稱的key
。 如果存在,則推送當前對象,否則創建一個key
並推送value
let data = [{ "published": true, "tags": ["tag1", "tag2"], "categories": ["cat1"], "author": "some name", "post-format": "standard", "title": "Second Post,", "url-slug": "second-post", "first-published-on": "2019-03-28", "last-updated-on": "2019-03-28", "meta": { "title": "Second Post", "description": "Second post." }, "excerpt": "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt", "path": "2019/03/28/SecondPost.md" }, { "published": true, "tags": ["tag1", "tag2", "tag3"], "categories": ["cat1", "cat2"], "author": "some name", "post-format": "standard", "title": "Getting Started", "url-slug": "getting-started", "first-published-on": "2019-03-20", "last-updated-on": "2019-03-20", "meta": { "title": "Getting Started", "description": "Getting started post." }, "excerpt": "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt", "path": "2019/03/20/GettingStarted.md" }]; let newMapped = [data.reduce(function(acc, curr) { curr.tags.forEach(function(item) { if (acc[item]) { acc[item].push(curr) } else { acc[item] = [curr] } }) return acc; }, {})]; console.log(newMapped)
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