What is a tag field and how do you implement it in typescript?

I am working on web app and I am new to this. I have done a little research but I did not find much; nevertheless, I did find a question here on StackOverflow which included a definition of a tag field:

A "tag field" or "dog tag" is a field you add to a structure solely for the purpose of error checking.

So, I am trying to add tag field to a model in a web app.

I think the model is implemented with an interface:

interface nameOfInterface {
   name: string;
   description: string;
   ...
}

The type of the tag field is an array of strings.

So how do you add a tag field(whose type is an array of strings) to a model in the context of web development in Typescript?

Thanks.