Toastr's api is very simple – only 4 methods.
// Display a info toast, with no title
toastr.info('Are you the six fingered man?')
// Display a warning toast, with no title
toastr.warning('My name is Inigo Montoya. You Killed my father, prepare to die!')
// Display a success toast, with a title
toastr.success('Have fun storming the castle!', 'Miracle Max Says')
// Display an error toast, with a title
toastr.error('I do not think that word means what you think it means.', 'Inconceivable!')
As with any app, I'm totally against letting vendor libraries infiltrate your app very far, so I'd suggest wrapping the above in a clientside lib that allows you to swap it out for the next best library when it arrives…