fix: simplify child array initialization in _array2tree function

Author: AxiosLeo

src/helper/convert.js

@@ -81,11 +81,7 @@ function _array2tree(data, options = {}) {
 
   const items = [];
   data.forEach(d => {
-    if (typeof d[c.child_name] === 'undefined') {
-      d[c.child_name] = [];
-    } else {
-      throw new Error('child name "' + c.child_name + '" is reserved for child data, please use another name');
-    }
+    d[c.child_name] = [];
     items[d[c.data_index]] = d;
     if (typeof d[c.parent_index] === 'undefined' || typeof d[c.data_index] === 'undefined') {
       throw new Error('data must have "' + c.parent_index + '" and "' + c.data_index + '"');

tests/convert.tests.js

@@ -50,7 +50,6 @@ describe('convert test case', function () {
     // throw error when data is not array
     expect(() => _array2tree(null)).to.throw('data must be an array');
     expect(() => _array2tree([{ id: 1 }])).to.throw('data must have "parent_id" and "id"');
-    expect(() => _array2tree([{ id: 1, parent_id: 0, child: [] }])).to.throw('child name "child" is reserved for child data, please use another name');
   });
 
   it('tree2array', function () {
@@ -70,7 +69,7 @@ describe('convert test case', function () {
                   {
                     'id': 4,
                     'parent_id': 2,
-                    'child': []
+                    'child': ''
                   }
                 ]
               }