JS converts a JSON array into a tree object

Yesterday encountered an interview problem, handwritten JS to convert the JSON array into a tree object, yesterday wrote wrong, today deliberately think of the next, the idea is actually quite simple, loop + recursive, Get child node object.

1 Let data = [2     {' parent_id ': 0, ' id ': 1, ' value ': ' XXX '},3     {' parent_id ': 1, ' ID ': 3, ' value ': ' xxx '},4     {' parent_id ': 4, ' ID ': 6, ' value ': ' xxx '}, C11>5     {' parent_id ': 3, ' ID ': 5, ' value ': ' XXX '},6     {' parent_id ': 2, ' ID ': 4, ' Value ': ' xxx '},7     {' parent_id ': 1, ' ID ': 2, ' value ': ' xxx '},8 ]

The main methods are as follows, using the ES6 syntax

1Let Totree = (arr, key = ' id ', Pkey = ' pid ', children= ' children ') = = {2      if(Arr.length = = 0){3          return {}4      }5      returnGetChildren (arr, 0)//the 0 here represents the root node, if the root node identifier is ' # ', then here is ' # '6       7   　　 //The main principle is to find the parent node parent_id as the PID of the object, and then one layer down to find the child node ID, see if there is parent_id equals ID of the object8      functionGetChildren (arr, pid) {9Let temp = {}TenArr.foreach (v = { One             if(V[pkey] = = =pid) { ATemp[v[key]] = {}//This can be adjusted to suit your needs -                 if(Object.keys (GetChildren (arr, V[key)). Length!== 0) {//If there are child nodes, the recursive method can also be extracted here to reduce the amount of code and the Operation -Temp[v[key]][children] = GetChildren (arr, V[key])//This can be adjusted to suit your needs the                 } -             } -         }) -         returnTemp +     } -}

Test data

1Let tree =totree (data)2 Console.log (Json.stringify (tree))3 4 //The result is:5 {6"1": {7"Children": {8"2": {9"Children": {Ten"4": { One"Children": { A"6": {} -                         } -                     } the                 } -             }, -"3": { -"Children": { +"5": {} -                 } +             } A         } at     } -}

JS converts a JSON array into a tree object