Validation 淘汰验证组错误

我试图将firstName、lastName和EmailAddess设置为要验证的观察值组

我一直得到的错误是“ChecklistForm未定义”

更新的视图模型：-

function checklistFormModel() {

 var ChecklistForm = {

    something: ko.observable(false),
    somethingElse: function () {},

    firstName: ko.observable().extend({
        minLength: 2,
        maxLength: 10
    }),
    lastName: ko.observable().extend({
        minLength: 2,
        maxLength: 10
    }),
    emailAddress: ko.observable().extend({
        email: true
    }),

    group: ko.validatedObservable({
        firstName: this.firstName,
        lastName: this.lastName,
        emailAddress: this.emailAddress
    }),

    submitForm: function () {
        console.log(this.group.errors());
        console.log(this.group.isValid());
    }
 }
  return ChecklistForm;
}
ko.applyBindings(checklistFormModel);

function checklistFormModel() {

 var ChecklistForm = {

    something: ko.observable(false),
    somethingElse: function () {},

    firstName: ko.observable().extend({
        minLength: 2,
        maxLength: 10
    }),
    lastName: ko.observable().extend({
        minLength: 2,
        maxLength: 10
    }),
    emailAddress: ko.observable().extend({
        email: true
    }),

    group: ko.validatedObservable({
        firstName: this.firstName,
        lastName: this.lastName,
        emailAddress: this.emailAddress
    }),

    submitForm: function () {
        console.log(this.group.errors());
        console.log(this.group.isValid());
    }
 }
  return ChecklistForm;
}
ko.applyBindings(checklistFormModel);