降低 Typescript/JS 中嵌套 object 数组的级别

Question

I'm learning TypeScript and Angular and I'm struggling with a problem. Say, I have an array of Application objects. Each Application object has this kind of a nested structure:

Application
|
----[Document Type]
---------|
--------------[Document]
------------------|
------------------------Metadata

(Each Application has an array of Document Type . Each Document Type has an array of Document . Each Document has a Metadata inside it)

Example:

[
 {
  "name": "Application 1",
  "parent_type": "root",
  "children": [
   {
    "name": "Operations Manual",
    "parent": "Application 1",
    "parent_type": "application",
    "count": 2,
    "children": [
     {
      "name": "App1-OpManual-1",
      "metadata": {
       "actualDocName": "operations1-app1",
       "currentStatus": "for review",
       "lastModifiedBy": "user 1",
       "size": 56,
       "fileExtension": "docx"
      }
     },
     {
      "name": "App1-OpManual-2",
      "metadata": {
       "actualDocName": "operations2-app1",
       "currentStatus": "for review",
       "lastModifiedBy": "user 2",
       "size": 56,
       "fileExtension": "pdf"
      }
     }
    ]
   }
  ]
 }
]

I'm trying to reduce this array to this (basically, to retain the nesting only till level 2 and discard the rest):

Application
|
----[Document Type]

..so that, the JSON becomes like this:

[
 {
  "name": "Application 1",
  "parent_type": "root",
  "children": [
   {
    "name": "Operations Manual",
    "parent": "Application 1",
    "parent_type": "application",
    "count": 2
   }
  ]
 }
] 

I've been trying with multiple examples from tutorials, but haven't been able to get the correct JS to do this. Can anybody please help?

Answer 1

You could use .map() and destructuring to grab the properties and values you need from your outer-most objects within your array, and then use .map() again with destructuring to get the properties you need fro your inner-most object to map each application object in your array to a newly created minified version of itself:

 const arr = [{name:"Application 1",parent_type:"root",children:[{name:"Operations Manual",parent:"Application 1",parent_type:"application",count:2,children:[{name:"App1-OpManual-1",metadata:{actualDocName:"operations1-app1",currentStatus:"for review",lastModifiedBy:"user 1",size:56,fileExtension:"docx"}},{name:"App1-OpManual-2",metadata:{actualDocName:"operations2-app1",currentStatus:"for review",lastModifiedBy:"user 2",size:56,fileExtension:"pdf"}}]}]}]; const res = arr.map(({children, ...r}) => ( {...r, children: children.map(({children, ...keep}) => ({...keep})) } )); console.log(res);