feat(tree): add clear()

tree/package.json

@@ -1,6 +1,6 @@
 {
   "name": "@sc/tree",
-  "version": "1.0.6",
+  "version": "1.0.7",
   "description": "a template for npm package coding",
   "main": "./dist/index.cjs.js",
   "module": "./dist/index.esm.js",

tree/src/tree.ts

@@ -593,4 +593,13 @@ export class Tree {
     this.updateValue(updateData);
     this.resortDataByID([orgParentID, newParentID]);
   }
+
+  // 清除所有节点（不变更data引用）
+  clear(): void {
+    this.rawData.splice(0, this.rawData.length);
+    this.data.splice(0, this.data.length);
+    this.parentMap = {};
+    this.IDMap = {};
+    this.ctxMap = {};
+  }
 }