feat(vc-collapse): key support number type #4405 (#4474)

close #4405

Author: John60676

components/vc-collapse/src/Collapse.jsx

@@ -11,11 +11,14 @@ import openAnimationFactory from './openAnimationFactory';
 import { collapseProps } from './commonProps';
 import { getDataAndAriaProps } from '../../_util/util';
 import { defineComponent } from 'vue';
+import isNil from 'lodash/isNil';
 
 function _toArray(activeKey) {
   let currentActiveKey = activeKey;
   if (!Array.isArray(currentActiveKey)) {
-    currentActiveKey = currentActiveKey ? [currentActiveKey] : [];
+    const activeKeyType = typeof currentActiveKey;
+    currentActiveKey =
+      activeKeyType === 'number' || activeKeyType === 'string' ? [currentActiveKey] : [];
   }
   return currentActiveKey.map(key => String(key));
 }
@@ -76,7 +79,7 @@ export default defineComponent({
       const { prefixCls, accordion, destroyInactivePanel, expandIcon } = this.$props;
 
       // If there is no key provide, use the panel order as default key
-      const key = child.key || String(index);
+      const key = !isNil(child.key) ? String(child.key) : String(index);
       const { header, headerClass, disabled } = getPropsData(child);
       let isActive = false;