tea

func Batch ¶

func Batch(cmds ...Cmd) Cmd

Batch performs a bunch of commands concurrently with no ordering guarantees about the results. Use a Batch to return several commands.

Example:

    func (m model) Init() Cmd {
	       return tea.Batch(someCommand, someOtherCommand)
    }

func Every ¶

func Every(duration time.Duration, fn func(time.Time) Msg) Cmd

Every is a command that ticks in sync with the system clock. So, if you wanted to tick with the system clock every second, minute or hour you could use this. It's also handy for having different things tick in sync.

Because we're ticking with the system clock the tick will likely not run for the entire specified duration. For example, if we're ticking for one minute and the clock is at 12:34:20 then the next tick will happen at 12:35:00, 40 seconds later.

To produce the command, pass a duration and a function which returns a message containing the time at which the tick occurred.

type TickMsg time.Time

cmd := Every(time.Second, func(t time.Time) Msg {
   return TickMsg(t)
})

Beginners' note: Every sends a single message and won't automatically dispatch messages at an interval. To do that, you'll want to return another Every command after receiving your tick message. For example:

type TickMsg time.Time

// Send a message every second.
func tickEvery() Cmd {
    return Every(time.Second, func(t time.Time) Msg {
        return TickMsg(t)
    })
}

func (m model) Init() Cmd {
    // Start ticking.
    return tickEvery()
}

func (m model) Update(msg Msg) (Model, Cmd) {
    switch msg.(type) {
    case TickMsg:
        // Return your Every command again to loop.
        return m, tickEvery()
    }
    return m, nil
}

Every is analogous to Tick in the Elm Architecture.

func Exec ¶

func Exec(c ExecCommand, fn ExecCallback) Cmd

Exec is used to perform arbitrary I/O in a blocking fashion, effectively pausing the Program while execution is running and resuming it when execution has completed.

Most of the time you'll want to use ExecProcess, which runs an exec.Cmd.

For non-interactive i/o you should use a Cmd (that is, a tea.Cmd).

func ExecProcess ¶

func ExecProcess(c *exec.Cmd, fn ExecCallback) Cmd

ExecProcess runs the given *exec.Cmd in a blocking fashion, effectively pausing the Program while the command is running. After the *exec.Cmd exists the Program resumes. It's useful for spawning other interactive applications such as editors and shells from within a Program.

To produce the command, pass an *exec.Cmd and a function which returns a message containing the error which may have occurred when running the ExecCommand.

type VimFinishedMsg struct { err error }

c := exec.Command("vim", "file.txt")

cmd := ExecProcess(c, func(err error) Msg {
    return VimFinishedMsg{err: err}
})

Or, if you don't care about errors, you could simply:

cmd := ExecProcess(exec.Command("vim", "file.txt"), nil)

For non-interactive i/o you should use a Cmd (that is, a tea.Cmd).

func Printf ¶

func Printf(template string, args ...interface{}) Cmd

Printf prints above the Program. It takes a format template followed by values similar to fmt.Printf. This output is unmanaged by the program and will persist across renders by the Program.

Unlike fmt.Printf (but similar to log.Printf) the message will be print on its own line.

If the altscreen is active no output will be printed.

func Println ¶

func Println(args ...interface{}) Cmd

Println prints above the Program. This output is unmanaged by the program and will persist across renders by the Program.

Unlike fmt.Println (but similar to log.Println) the message will be print on its own line.

If the altscreen is active no output will be printed.

func ScrollDown ¶

func ScrollDown(newLines []string, topBoundary, bottomBoundary int) Cmd

ScrollDown adds lines to the bottom of the scrollable region, pushing existing lines above up. Lines that are pushed out of the scrollable region disappear from view.

For high-performance, scroll-based rendering only.

func ScrollUp ¶

func ScrollUp(newLines []string, topBoundary, bottomBoundary int) Cmd

ScrollUp adds lines to the top of the scrollable region, pushing existing lines below down. Lines that are pushed out the scrollable region disappear from view.

For high-performance, scroll-based rendering only.

func Sequence ¶

func Sequence(cmds ...Cmd) Cmd

Sequence runs the given commands one at a time, in order. Contrast this with Batch, which runs commands concurrently.

func SetWindowTitle ¶

func SetWindowTitle(title string) Cmd

SetWindowTitle produces a command that sets the terminal title.

For example:

func (m model) Init() Cmd {
    // Set title.
    return tea.SetWindowTitle("My App")
}

func SyncScrollArea ¶

func SyncScrollArea(lines []string, topBoundary int, bottomBoundary int) Cmd

SyncScrollArea performs a paint of the entire region designated to be the scrollable area. This is required to initialize the scrollable region and should also be called on resize (WindowSizeMsg).

For high-performance, scroll-based rendering only.

func Tick ¶

func Tick(d time.Duration, fn func(time.Time) Msg) Cmd

Tick produces a command at an interval independent of the system clock at the given duration. That is, the timer begins precisely when invoked, and runs for its entire duration.

To produce the command, pass a duration and a function which returns a message containing the time at which the tick occurred.

type TickMsg time.Time

cmd := Tick(time.Second, func(t time.Time) Msg {
   return TickMsg(t)
})

Beginners' note: Tick sends a single message and won't automatically dispatch messages at an interval. To do that, you'll want to return another Tick command after receiving your tick message. For example:

type TickMsg time.Time

func doTick() Cmd {
    return Tick(time.Second, func(t time.Time) Msg {
        return TickMsg(t)
    })
}

func (m model) Init() Cmd {
    // Start ticking.
    return doTick()
}

func (m model) Update(msg Msg) (Model, Cmd) {
    switch msg.(type) {
    case TickMsg:
        // Return your Tick command again to loop.
        return m, doTick()
    }
    return m, nil
}

func ClearScreen ¶

func ClearScreen() Msg

ClearScreen is a special command that tells the program to clear the screen before the next update. This can be used to move the cursor to the top left of the screen and clear visual clutter when the alt screen is not in use.

Note that it should never be necessary to call ClearScreen() for regular redraws.

func ClearScrollArea ¶

func ClearScrollArea() Msg

ClearScrollArea deallocates the scrollable region and returns the control of those lines to the main rendering routine.

For high-performance, scroll-based rendering only.

func DisableBracketedPaste ¶

func DisableBracketedPaste() Msg

DisableBracketedPaste is a special command that tells the Bubble Tea program to accept bracketed paste input.

Note that bracketed paste will be automatically disabled when the program quits.

func DisableMouse ¶

func DisableMouse() Msg

DisableMouse is a special command that stops listening for mouse events.

func EnableBracketedPaste ¶

func EnableBracketedPaste() Msg

EnableBracketedPaste is a special command that tells the Bubble Tea program to accept bracketed paste input.

Note that bracketed paste will be automatically disabled when the program quits.

func EnableMouseAllMotion ¶

func EnableMouseAllMotion() Msg

EnableMouseAllMotion is a special command that enables mouse click, release, wheel, and motion events, which are delivered regardless of whether a mouse button is pressed, effectively enabling support for hover interactions.

Many modern terminals support this, but not all. If in doubt, use EnableMouseCellMotion instead.

Because commands run asynchronously, this command should not be used in your model's Init function. Use the WithMouseAllMotion ProgramOption instead.

func EnableMouseCellMotion ¶

func EnableMouseCellMotion() Msg

EnableMouseCellMotion is a special command that enables mouse click, release, and wheel events. Mouse movement events are also captured if a mouse button is pressed (i.e., drag events).

Because commands run asynchronously, this command should not be used in your model's Init function. Use the WithMouseCellMotion ProgramOption instead.

func EnterAltScreen ¶

func EnterAltScreen() Msg

EnterAltScreen is a special command that tells the Bubble Tea program to enter the alternate screen buffer.

Because commands run asynchronously, this command should not be used in your model's Init function. To initialize your program with the altscreen enabled use the WithAltScreen ProgramOption instead.

func ExitAltScreen ¶

func ExitAltScreen() Msg

ExitAltScreen is a special command that tells the Bubble Tea program to exit the alternate screen buffer. This command should be used to exit the alternate screen buffer while the program is running.

Note that the alternate screen buffer will be automatically exited when the program quits.

func HideCursor ¶

func HideCursor() Msg

HideCursor is a special command for manually instructing Bubble Tea to hide the cursor. In some rare cases, certain operations will cause the terminal to show the cursor, which is normally hidden for the duration of a Bubble Tea program's lifetime. You will most likely not need to use this command.

func Quit ¶

func Quit() Msg

Quit is a special command that tells the Bubble Tea program to exit.

func ShowCursor ¶

func ShowCursor() Msg

ShowCursor is a special command for manually instructing Bubble Tea to show the cursor.

func NewProgram ¶

func NewProgram(model Model, opts ...ProgramOption) *Program

NewProgram creates a new Program.

func WithANSICompressor ¶

func WithANSICompressor() ProgramOption

WithANSICompressor removes redundant ANSI sequences to produce potentially smaller output, at the cost of some processing overhead.

This feature is provisional, and may be changed or removed in a future version of this package.

func WithAltScreen ¶

func WithAltScreen() ProgramOption

WithAltScreen starts the program with the alternate screen buffer enabled (i.e. the program starts in full window mode). Note that the altscreen will be automatically exited when the program quits.

Example:

p := tea.NewProgram(Model{}, tea.WithAltScreen())
if _, err := p.Run(); err != nil {
    fmt.Println("Error running program:", err)
    os.Exit(1)
}

To enter the altscreen once the program has already started running use the EnterAltScreen command.

func WithContext ¶

func WithContext(ctx context.Context) ProgramOption

WithContext lets you specify a context in which to run the Program. This is useful if you want to cancel the execution from outside. When a Program gets cancelled it will exit with an error ErrProgramKilled.

func WithFPS ¶

func WithFPS(fps int) ProgramOption

WithFPS sets a custom maximum FPS at which the renderer should run. If less than 1, the default value of 60 will be used. If over 120, the FPS will be capped at 120.

func WithFilter ¶

func WithFilter(filter func(Model, Msg) Msg) ProgramOption

WithFilter supplies an event filter that will be invoked before Bubble Tea processes a tea.Msg. The event filter can return any tea.Msg which will then get handled by Bubble Tea instead of the original event. If the event filter returns nil, the event will be ignored and Bubble Tea will not process it.

As an example, this could be used to prevent a program from shutting down if there are unsaved changes.

Example:

func filter(m tea.Model, msg tea.Msg) tea.Msg {
	if _, ok := msg.(tea.QuitMsg); !ok {
		return msg
	}

	model := m.(myModel)
	if model.hasChanges {
		return nil
	}

	return msg
}

p := tea.NewProgram(Model{}, tea.WithFilter(filter));

if _,err := p.Run(); err != nil {
	fmt.Println("Error running program:", err)
	os.Exit(1)
}

func WithInput ¶

func WithInput(input io.Reader) ProgramOption

WithInput sets the input which, by default, is stdin. In most cases you won't need to use this. To disable input entirely pass nil.

p := NewProgram(model, WithInput(nil))

func WithInputTTY ¶

func WithInputTTY() ProgramOption

WithInputTTY opens a new TTY for input (or console input device on Windows).

func WithMouseAllMotion ¶

func WithMouseAllMotion() ProgramOption

WithMouseAllMotion starts the program with the mouse enabled in "all motion" mode.

EnableMouseAllMotion is a special command that enables mouse click, release, wheel, and motion events, which are delivered regardless of whether a mouse button is pressed, effectively enabling support for hover interactions.

This will try to enable the mouse in extended mode (SGR), if that is not supported by the terminal it will fall back to normal mode (X10).

Many modern terminals support this, but not all. If in doubt, use EnableMouseCellMotion instead.

To enable the mouse once the program has already started running use the EnableMouseAllMotion command. To disable the mouse when the program is running use the DisableMouse command.

The mouse will be automatically disabled when the program exits.

func WithMouseCellMotion ¶

func WithMouseCellMotion() ProgramOption

WithMouseCellMotion starts the program with the mouse enabled in "cell motion" mode.

Cell motion mode enables mouse click, release, and wheel events. Mouse movement events are also captured if a mouse button is pressed (i.e., drag events). Cell motion mode is better supported than all motion mode.

This will try to enable the mouse in extended mode (SGR), if that is not supported by the terminal it will fall back to normal mode (X10).

To enable mouse cell motion once the program has already started running use the EnableMouseCellMotion command. To disable the mouse when the program is running use the DisableMouse command.

The mouse will be automatically disabled when the program exits.

func WithOutput ¶

func WithOutput(output io.Writer) ProgramOption

WithOutput sets the output which, by default, is stdout. In most cases you won't need to use this.

func WithRenderer ¶

func WithRenderer(renderer Renderer) ProgramOption

func WithoutBracketedPaste ¶

func WithoutBracketedPaste() ProgramOption

WithoutBracketedPaste starts the program with bracketed paste disabled.

func WithoutCatchPanics ¶

func WithoutCatchPanics() ProgramOption

WithoutCatchPanics disables the panic catching that Bubble Tea does by default. If panic catching is disabled the terminal will be in a fairly unusable state after a panic because Bubble Tea will not perform its usual cleanup on exit.

func WithoutRenderer ¶

func WithoutRenderer() ProgramOption

WithoutRenderer disables the renderer. When this is set output and log statements will be plainly sent to stdout (or another output if one is set) without any rendering and redrawing logic. In other words, printing and logging will behave the same way it would in a non-TUI commandline tool. This can be useful if you want to use the Bubble Tea framework for a non-TUI application, or to provide an additional non-TUI mode to your Bubble Tea programs. For example, your program could behave like a daemon if output is not a TTY.

func WithoutSignalHandler ¶

func WithoutSignalHandler() ProgramOption

WithoutSignalHandler disables the signal handler that Bubble Tea sets up for Programs. This is useful if you want to handle signals yourself.

func WithoutSignals ¶

func WithoutSignals() ProgramOption

WithoutSignals will ignore OS signals. This is mainly useful for testing.