Create option to maintain structure of your data.

README.md

@@ -61,6 +61,7 @@ You can provide a second argument to arrayToTree with configuration options. Rig
 
 - `id`: key of the id field of the item
 - `parentId`: key of the parent's id field of the item
+- `maintainStructure`: boolean to keep the current structure of your data. Not put it in a `data` field
 
 Example:
 
@@ -71,7 +72,7 @@ const tree = arrayToTree([
  { num: '1941', ref: '418', custom: 'de' },
  { num: '1', ref: '418', custom: 'ZZZz' },
  { num: '418', ref: null, custom: 'ü'},
-], { id: 'num', parentId: 'ref' })
+], { id: 'num', parentId: 'ref', maintainStructure: false })
 ```
 
 Which produces:
@@ -88,6 +89,32 @@ Which produces:
 ]
 ```
 
+Example:
+
+```js
+const tree = arrayToTree([
+ { num: '4', ref: null, custom: 'abc' },
+ { num: '31', ref: '4', custom: '12' },
+ { num: '1941', ref: '418', custom: 'de' },
+ { num: '1', ref: '418', custom: 'ZZZz' },
+ { num: '418', ref: null, custom: 'ü'},
+], { id: 'num', parentId: 'ref', maintainStructure: true })
+```
+
+Which produces:
+
+```js
+[
+ { num: '4', ref: null, custom: 'abc', children: [
+ { num: '31', ref: '4', custom: '12', children: [] },
+ ] },
+ { num: '418', ref: null, custom: 'ü', children: [
+ { num: '1941', ref: '418', custom: 'de', children: [] },
+ { num: '1', ref: '418', custom: 'ZZZz', children: [] },
+ ] },
+]
+```
+
 ## TypeScript
 
 This project includes types, just import the module as usual:

src/arrayToTree.spec.ts

@@ -33,7 +33,7 @@ describe('arrayToTree', () => {
  { num: '1', ref: '418', custom: 'ZZZz' },
  { num: '418', ref: null, custom: 'ü' },
  ] as any),
- { id: 'num', parentId: 'ref' },
+ { id: 'num', parentId: 'ref', maintainStructure: false },
  )).to.deep.equal([
  {
  data: { num: '4', ref: null, custom: 'abc' }, children: [
@@ -72,6 +72,81 @@ describe('arrayToTree', () => {
  ])
  })
 
+ it('should work with nested objects structure maintained', () => {
+ expect(arrayToTree(
+ ([
+ { id: '4', parentId: null, custom: 'abc' },
+ { id: '31', parentId: '4', custom: '12' },
+ { id: '1941', parentId: '418', custom: 'de' },
+ { id: '1', parentId: '418', custom: 'ZZZz' },
+ { id: '418', parentId: null, custom: 'ü' },
+ ] as any),
+ { id: 'id', parentId: 'parentId', maintainStructure: true },
+ )).to.deep.equal([
+ {
+ id: '4', parentId: null, custom: 'abc', children: [
+ { id: '31', parentId: '4', custom: '12', children: [] },
+ ],
+ },
+ {
+ id: '418', parentId: null, custom: 'ü', children: [
+ { id: '1941', parentId: '418', custom: 'de', children: [] },
+ { id: '1', parentId: '418', custom: 'ZZZz', children: [] },
+ ],
+ },
+ ])
+ })
+
+ it('should work with nested objects and custom keys structure maintained', () => {
+ expect(arrayToTree(
+ ([
+ { num: '4', ref: null, custom: 'abc' },
+ { num: '31', ref: '4', custom: '12' },
+ { num: '1941', ref: '418', custom: 'de' },
+ { num: '1', ref: '418', custom: 'ZZZz' },
+ { num: '418', ref: null, custom: 'ü' },
+ ] as any),
+ { id: 'num', parentId: 'ref', maintainStructure: true },
+ )).to.deep.equal([
+ {
+ num: '4', ref: null, custom: 'abc', children: [
+ { num: '31', ref: '4', custom: '12', children: [] },
+ ],
+ },
+ {
+ num: '418', ref: null, custom: 'ü', children: [
+ { num: '1941', ref: '418', custom: 'de', children: [] },
+ { num: '1', ref: '418', custom: 'ZZZz', children: [] },
+ ],
+ },
+ ])
+ })
+
+ it('should ignore objects if parentId does not exist structure maintained', () => {
+ expect(arrayToTree(
+ ([
+ { id: '4', parentId: null, custom: 'abc' },
+ { id: '31', parentId: '4', custom: '12' },
+ { id: '1941', parentId: '418', custom: 'de' },
+ { id: '1', parentId: '418', custom: 'ZZZz' },
+ { id: '418', parentId: null, custom: 'ü' },
+ ] as any),
+ { id: 'id', parentId: 'parentId', maintainStructure: true },
+ )).to.deep.equal([
+ {
+ id: '4', parentId: null, custom: 'abc', children: [
+ { id: '31', parentId: '4', custom: '12', children: [] },
+ ],
+ },
+ {
+ id: '418', parentId: null, custom: 'ü', children: [
+ { id: '1941', parentId: '418', custom: 'de', children: [] },
+ { id: '1', parentId: '418', custom: 'ZZZz', children: [] },
+ ],
+ },
+ ])
+ })
+
  it('should work with empty inputs', () => {
  expect(arrayToTree([])).to.deep.equal([])
  })

src/arrayToTree.ts

@@ -5,19 +5,20 @@ export interface Item {
 }
 
 export interface TreeItem {
- data: Item | null
+ [key: string]: any,
  children: TreeItem[]
 }
 
 export interface Config {
  id: string,
  parentId: string,
+ maintainStructure: boolean,
 }
 
 /**
  * Unflattens an array to a tree with runtime O(n)
  */
-export function arrayToTree (items: Item[], config: Config = { id: 'id', parentId: 'parentId' }): TreeItem[] {
+export function arrayToTree (items: Item[], config: Config = { id: 'id', parentId: 'parentId', maintainStructure: false }): TreeItem[] {
  // the resulting unflattened tree
  const rootItems: TreeItem[] = []
 
@@ -35,11 +36,19 @@ export function arrayToTree (items: Item[], config: Config = { id: 'id', parentI
  // look whether item already exists in the lookup table
  if (!Object.prototype.hasOwnProperty.call(lookup, itemId)) {
  // item is not yet there, so add a preliminary item (its data will be added later)
- lookup[itemId] = { data: null, children: [] }
+ if(config.maintainStructure){
+ lookup[itemId] = { children: [] }
+ } else {
+ lookup[itemId] = { data: null, children: [] }
+ }
  }
 
  // add the current item's data to the item in the lookup table
- lookup[itemId].data = item
+ if(config.maintainStructure) {
+ lookup[itemId] = {children: lookup[itemId].children, ...item}
+ } else {
+ lookup[itemId].data = item
+ }
 
  const TreeItem = lookup[itemId]
 
@@ -52,7 +61,11 @@ export function arrayToTree (items: Item[], config: Config = { id: 'id', parentI
  // look whether the parent already exists in the lookup table
  if (!Object.prototype.hasOwnProperty.call(lookup, parentId)) {
  // parent is not yet there, so add a preliminary parent (its data will be added later)
- lookup[parentId] = { data: null, children: [] }
+ if(config.maintainStructure){
+ lookup[parentId] = { children: [] }
+ } else {
+ lookup[parentId] = { data: null, children: [] }
+ }
  }
 
  // add the current item to the parent