addTag(): string | null
Adds a tag to the given TagsInterface.
If a tag with the same name already exists, its value is updated.
taggable: TagsInterface
- The entity to which the tag will be added.
name: string
- The name of the tag.
value: string
- The value of the tag.
string | null
The previous value of the tag if it was updated, or null if it was added.