TabsetComponentthrowingTypeError

Hello, I am facing a problem with TabsetComponent (manual selection) while following up with a tutorial that was done with Angular6, its throwing "ERROR TypeError: Cannot read property 'tabs' of undefined" when I check using chrome tools. I am using Angular7 and I have counter checked and everything looks okay. Below is the link of the component throwing the error
https://github.com/pmakanga/DatingApp/blob/master/DatingApp-SPA/src/app/members/member-detail/member-detail.component.ts

Have used:
('memberTabs') memberTabs: TabsetComponent;

And the calling method as below

selectTab(tabId: number) {
this.memberTabs.tabs[tabId].active = true;
}

The angular html component is on the below link
https://github.com/pmakanga/DatingApp/blob/master/DatingApp-SPA/src/app/members/member-detail/member-detail.component.html

The tab is being called with the below method
Message

该提问来源于开源项目：valor-software/ngx-bootstrap