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go-fuzzyfinder is a Go library that provides fuzzy-finding with an fzf-like terminal user interface.


$ go get


go-fuzzyfinder provides two functions, Find and FindMulti. FindMulti can select multiple lines. It is similar to fzf -m.

This is an example of FindMulti.

type Track struct {
    Name      string
    AlbumName string
    Artist    string

var tracks = []Track{
    {"foo", "album1", "artist1"},
    {"bar", "album1", "artist1"},
    {"foo", "album2", "artist1"},
    {"baz", "album2", "artist2"},
    {"baz", "album3", "artist2"},

func main() {
    idx, err := fuzzyfinder.FindMulti(
        func(i int) string {
            return tracks[i].Name
        fuzzyfinder.WithPreviewWindow(func(i, w, h int) string {
            if i == -1 {
                return ""
            return fmt.Sprintf("Track: %s (%s)\nAlbum: %s",
    if err != nil {
    fmt.Printf("selected: %v\n", idx)

The execution result prints selected item's indexes.


Fuzzy-finder command-line tools such that fzf, fzy, or skim are very powerful to find out specified lines interactively. However, there are limits to deal with fuzzy-finder's features in several cases.

First, it is hard to distinguish between two or more entities that have the same text. In the example of ktr0731/itunes-cli, it is possible to conflict tracks such that same track names, but different artists. To avoid such conflicts, we have to display the artist names with each track name. It seems like the problem has been solved, but it still has the problem. It is possible to conflict in case of same track names, same artists, but other albums, which each track belongs to. This problem is difficult to solve because pipes and filters are row-based mechanisms, there are no ways to hold references that point list entities.

The second issue occurs in the case of incorporating a fuzzy-finder as one of the main features in a command-line tool such that enhancd or itunes-cli. Usually, these tools require that it has been installed one fuzzy-finder as a precondition. In addition, to deal with the fuzzy-finder, an environment variable configuration such that export TOOL_NAME_FINDER=fzf is required. It is a bother and complicated.

go-fuzzyfinder resolves above issues. Dealing with the first issue, go-fuzzyfinder provides the preview-window feature (See an example in Usage). Also, by using go-fuzzyfinder, built tools don't require any fuzzy-finders.

See Also

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    Package fuzzyfinder provides terminal user interfaces for fuzzy-finding.

    Note that, all functions are not goroutine-safe.




    View Source
    const (
    	// ModeSmart enables a smart matching. It is the default matching mode.
    	// At the beginning, matching mode is ModeCaseInsensitive, but it switches
    	// over to ModeCaseSensitive if an upper case character is inputted.
    	ModeSmart mode = iota
    	// ModeCaseSensitive enables a case-sensitive matching.
    	// ModeCaseInsensitive enables a case-insensitive matching.


    View Source
    var (
    	// ErrAbort is returned from Find* functions if there are no selections.
    	ErrAbort = errors.New("abort")


    func Find

    func Find(slice interface{}, itemFunc func(i int) string, opts ...Option) (int, error)

      Find displays a UI that provides fuzzy finding against the provided slice. The argument slice must be of a slice type. If not, Find returns an error. itemFunc is called by the length of slice. previewFunc is called when the cursor which points to the currently selected item is changed. If itemFunc is nil, Find returns an error.

      itemFunc receives an argument i, which is the index of the item currently selected.

      Find returns ErrAbort if a call to Find is finished with no selection.

      Example (PreviewWindow)

      func FindMulti

      func FindMulti(slice interface{}, itemFunc func(i int) string, opts ...Option) ([]int, error)

        FindMulti is nearly the same as Find. The only difference from Find is that the user can select multiple items at once, by using the tab key.



        type Option

        type Option func(*opt)

          Option represents available fuzzy-finding options.

          func WithHotReload

          func WithHotReload() Option

            WithHotReload reloads the passed slice automatically when some entries are appended. The caller must pass a pointer of the slice instead of the slice itself.

            func WithMode

            func WithMode(m mode) Option

              WithMode specifies a matching mode. The default mode is ModeSmart.

              func WithPreviewWindow

              func WithPreviewWindow(f func(i, width, height int) string) Option

                WithPreviewWindow enables to display a preview for the selected item. The argument f receives i, width and height. i is the same as Find's one. width and height are the size of the terminal so that you can use these to adjust a preview content. Note that width and height are calculated as a rune-based length.

                If there is no selected item, previewFunc passes -1 to previewFunc.

                If f is nil, the preview feature is disabled.

                func WithPromptString

                func WithPromptString(s string) Option

                  WithPromptString changes the prompt string. The default value is "> ".

                  type TerminalMock

                  type TerminalMock struct {
                  	// contains filtered or unexported fields

                    TerminalMock is a mocked terminal for testing. Most users should use it by calling UseMockedTerminal.


                    func UseMockedTerminal

                    func UseMockedTerminal() *TerminalMock

                      UseMockedTerminal switches the terminal, which is used from this package to a mocked one.

                      func (*TerminalMock) GetResult

                      func (m *TerminalMock) GetResult() string

                        GetResult returns a flushed string that is displayed to the actual terminal. It contains all escape sequences such that ANSI escape code.

                        func (*TerminalMock) SetEvents

                        func (m *TerminalMock) SetEvents(e ...termbox.Event)

                          SetEvents sets all events, which are fetched by pollEvent. A user of this must set the EscKey event at the end.

                          func (*TerminalMock) SetSize

                          func (m *TerminalMock) SetSize(w, h int)

                            SetSize changes the pseudo-size of the window. Note that SetSize resets added cells.


                            Path Synopsis
                            Package matching provides matching features that find appropriate strings by using a passed input string.
                            Package matching provides matching features that find appropriate strings by using a passed input string.
                            Package scoring provides APIs that calculates similarity scores between two strings.
                            Package scoring provides APIs that calculates similarity scores between two strings.