install gulp to process code

node_modules/gulp-cli/lib/versioned/^3.7.0/task-tree.js

@@ -0,0 +1,27 @@
+'use strict';
+
+module.exports = function(tasks) {
+  var map = {};
+  var arr = [];
+  Object.keys(tasks).forEach(function(taskname) {
+    var task = {
+      label: taskname,
+      type: 'task',
+      nodes: [],
+    };
+    map[taskname] = task;
+    arr.push(task);
+  });
+  Object.keys(tasks).forEach(function(taskname) {
+    var task = map[taskname];
+    tasks[taskname].dep.forEach(function(childname) {
+      var child = map[childname] || {
+        label: childname,
+        type: 'task',
+        nodes: [],
+      };
+      task.nodes.push(child);
+    });
+  });
+  return { label: 'Tasks', nodes: arr };
+};