The "clear current line and reprint" doesn't work with long suffix about spinner

[gbouv]

This can be "easily" fixed with the following spinner:

spin := spinner.New(spinner.CharSets[11], 100*time.Millisecond, spinner.WithSuffix(suffix))
spin.PreUpdate = func(s *spinner.Spinner) {
    fmt.Print("\0337\033[J") // save cursor position and erase everything until end of screen
}
spin.PostUpdate = func(s *spinner.Spinner) {
    fmt.Print("\0338")  // restore cursor position
}

But I would have expected the spinner to handle it by itself

Also, the downside of doing \033[J in the PreUpdate is that we're clearing current line twice, which is unnecessary

[gbouv]

In fact the above "hack" doesn't even work when we start printing at the bottom of the terminal because scrolling messes up with the saved position.
So, I had to implement the actual fix of computing in advance how many lines will be needed to print the entire "spinner + suffix" string, and clearing this exact number of lines on every update in the PreUpdate function. It seems to be the only working solution

[briandowns]

Care to share your solution or submit a PR?

[gbouv]

Yup @briandowns I'll submit a PR and tag you on it in the next few days when I have a bit more bandwidth 👍

[gbouv]

@briandowns sorry it took so long, but the PR is up and ready for review: #146
Let me know what you think