Data format conversion: converting flat arrays to tree json

[
  {source: "001", target: "002", weight: 10},
  {source: "001", target: "003", weight: 15},
  {source: "002", target: "004", weight: 12},
  {source: "004", target: "005", weight: 10},
 ....
]

convert to 

[
  {
  id: "001",
  children: [
    {
      id: "002",
      weight: 10,
      children: [
        {
          id: "004",
          weight: 12,
          children: [
            {
              id: "005",
              weight: 10
            }
          ]
        }
      ]
    },
    {
      id: "003",
      weight: 15,
      children: []
    }
   ]
  }
]
Javascript
Mar.10,2021

build all the trees in a loop, and then find the root node and push it in. 

let arr = [...]
let sidMap = {}
let map= {} 
for(let i=0 ;i<arr.length;iPP){
    let pid = arr[i].source
    let sid = arr[i].target
    if(!map[sid]){
        map[sid]={id:sid, children:[]}
    }
    map[sid].weight = arr[i].weight
    if(!map[pid]){
        map[pid]={id:pid, children:[]}
    }
    map[pid].children.push(map[sid])
    sidMap[sid]=true
}
let ans = []
for(let i=0 ;i<arr.length;iPP){
    let pid = arr[i].source
    if(!sidMap[pid]){
        sidMap[pid] = true
        ans.push(map[pid])
    }
}
console.log(ans)
  
 two for loops 
 set an object ob 
 put all objects of the same source together 
 and {2: [{.}, {.}],} 
 the second time for can operate according to the above object 
 the specific code is not posted

Previous: Problems with Firefox console output objects

Next: How does vscode start webpack for packaging?

css mysql arrays josn react html typescript webpack npm sass R objective-c .net sql-server jquery python-3.x angularjs django angular excel regex iphone ajax linux xml pandas vba spring database wordpress string wpf xcode windows bash postgresql oracle multithreading eclipse list firebase algorithm macos forms image scala visual-studio azure bootstrap spring-boot react-native python-2.7 docker performance function winforms matlab powershell apache dataframe api sqlite numpy rest shell selenium flutter dart maven loops qt swing android-studio csv express file class tensorflow sorting codeigniter perl
MySQL Query : SELECT * FROM `codeshelper`.`v9_news` WHERE status=99 AND catid='6' ORDER BY rand() LIMIT 5
MySQL Error : Disk full (/tmp/#sql-temptable-64f5-1e44e34-437a9.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
MySQL Errno : 1021
Message : Disk full (/tmp/#sql-temptable-64f5-1e44e34-437a9.MAI); waiting for someone to free some space... (errno: 28 "No space left on device")
Need Help?