bubbletea/commands.go

78 lines
2.1 KiB
Go

package tea
// Convenience commands. Not part of the Bubble Tea core, but potentially
// handy.
import (
"time"
)
// 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)
// })
func Every(duration time.Duration, fn func(time.Time) Msg) Cmd {
return func() Msg {
n := time.Now()
d := n.Truncate(duration).Add(duration).Sub(n)
t := time.NewTimer(d)
return fn(<-t.C)
}
}
// Tick produces a command at an interval independent of the system clock at
// the given duration. That is, the timer begins when 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)
// })
func Tick(d time.Duration, fn func(time.Time) Msg) Cmd {
return func() Msg {
t := time.NewTimer(d)
return fn(<-t.C)
}
}
// Sequentially produces a command that sequentially executes the given
// commands.
// The Msg returned is the first non-nil message returned by a Cmd.
//
// func saveStateCmd() Msg {
// if err := save(); err != nil {
// return errMsg{err}
// }
// return nil
// }
//
// cmd := Sequentially(saveStateCmd, Quit)
//
func Sequentially(cmds ...Cmd) Cmd {
return func() Msg {
for _, cmd := range cmds {
if msg := cmd(); msg != nil {
return msg
}
}
return nil
}
}