基于jeecgboot的flowable流程设计器的用户选择问题修复

changeDataType(val) {
      // 清空 userTaskForm 所有属性值
      //Object.keys(this.userTaskForm).forEach(key => this.userTaskForm[key] = null);
      this.userTaskForm.dataType = val;
      if (val === 'INITIATOR') {
        this.userTaskForm.assignee = "${INITIATOR}";
        this.userTaskForm.text = "流程发起人";
        const taskAttr = Object.create(null);
        taskAttr['candidateUsers'] = null;
        taskAttr['candidateGroups'] = null;
        this.userTaskForm['candidateUsers'] = null;
        this.userTaskForm['candidateGroups'] = null;
        taskAttr['assignee'] = this.userTaskForm['assignee'] || null;
        window.bpmnInstances.modeling.updateProperties(this.bpmnElement, taskAttr);
      }
      if (val === 'ASSIGNEE' && this.userTaskForm['assignee'] === '${INITIATOR}') {
        this.userTaskForm['assignee'] = null;
        const taskAttr = Object.create(null);
        taskAttr['assignee'] = null;
        window.bpmnInstances.modeling.updateProperties(this.bpmnElement, taskAttr);
      }
    },

updateElementTask(key) {
      const taskAttr = Object.create(null);
      if (key === "candidateUsers") {
        taskAttr[key] = this.userTaskForm[key] && this.userTaskForm[key].length ? this.userTaskForm[key].join() : null;
        if(taskAttr[key] !=null) {
          taskAttr['candidateGroups'] = null;
          taskAttr['assignee'] = null;
          this.userTaskForm['candidateGroups'] = null;
          this.userTaskForm['assignee'] = null;
        }  
      } 
      else if (key === "candidateGroups") {
        taskAttr[key] = this.userTaskForm[key] && this.userTaskForm[key].length ? this.userTaskForm[key].join() : null;
        if(taskAttr[key] !=null) {
          taskAttr['candidateUsers'] = null;
          taskAttr['assignee'] = null;
          this.userTaskForm['candidateUsers'] = null;
          this.userTaskForm['assignee'] = null;
        }  
      } 
      else if (key === "assignee") {
        taskAttr[key] = this.userTaskForm[key] && this.userTaskForm[key].length ? this.userTaskForm[key] : null;
        if(taskAttr[key] !=null) {
          taskAttr['candidateUsers'] = null;
          taskAttr['candidateGroups'] = null;
          this.userTaskForm['candidateUsers'] = null;
          this.userTaskForm['candidateGroups'] = null;
        }
      } 
      else {
        taskAttr[key] = this.userTaskForm[key] || null;
      }
      window.bpmnInstances.modeling.updateProperties(this.bpmnElement, taskAttr);
    }
  },