On the Complete Poems of Emily Dickinson

I can’t say I read all of Emily Dickinson’s poems, but I have read a large number of them over the past few months and they are generally quite short and good. The only thing is that I can’t figure out what to do with all of her “—” or what they mean. Is it a pause? Does it have some meaning I don’t quite understand? I’ve tried looking it up and haven’t really found a satisfactory answer. Nevertheless, if there’s one single nineteenth century American poet that everyone needs to read, I’d recommend Dickinson over Whitman, although both are critical.