ADD: get category tree logic function

components/category/categoryService.js

@@ -1,6 +1,60 @@
 const Category = require('./categoryModel')
 const AppError = require('../../globalErrorHandler/AppError')
 
+module.exports.getCategoryTree = async () => {
+    const nodes = await Category.find({})
+    let tree = []
+    for (let i = 0; i < nodes.length; i++) {
+        if (!nodes[i].parentId) {
+            const label = nodes[i].nativeName
+            const children = []
+            const key = nodes[i]._id.toString()
+            const href = '/categories/admin/update/' + nodes[i]._id
+            const a_attr = { href }
+            const root = { label, children, key, a_attr }
+            tree.push(root)
+        }
+    }
+
+    tree = recursiveFunction(tree, nodes)
+    return tree
+}
+
+const recursiveFunction = (tree, categories) => {
+    if (tree.length > 0) {
+        for (let i = 0; i < tree.length; i++) {
+            let subTree = []
+            for (let j = 0; j < categories.length; j++) {
+                if (tree[i].key === categories[j].parentId?.toString()) {
+                    const label = categories[j].nativeName.toString()
+                    const children = []
+                    const key = categories[j]._id.toString()
+                    const href = '/categories/admin/update/' + categories[j]._id
+                    const a_attr = { href }
+                    subTree.push({ label, children, key, a_attr })
+                }
+                let index = findCategoryIndex(tree, tree[i].label)
+                tree[index].children = subTree
+            }
+        }
+        for (let i = 0; i < tree.length; i++) {
+            let index = findCategoryIndex(tree, tree[i].label)
+            recursiveFunction(tree[index].children, categories)
+        }
+    }
+    return tree
+}
+
+function findCategoryIndex(array, label) {
+    let index
+    for (let i = 0; i < array.length; i++) {
+        if (array[i].label === label) {
+            index = i
+            return index
+        }
+    }
+}
+
 module.exports.getAllCategories = async () => {
     return Category.find().populate('parentId')
 }