chore: reorganize command helpers

commands.go

@@ -1,12 +1,48 @@
 package tea
 
-// Convenience commands. Not part of the Bubble Tea core, but potentially
-// handy.
-
 import (
 	"time"
 )
 
+// 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 Batch(cmds ...Cmd) Cmd {
+	var validCmds []Cmd
+	for _, c := range cmds {
+		if c == nil {
+			continue
+		}
+		validCmds = append(validCmds, c)
+	}
+	if len(validCmds) == 0 {
+		return nil
+	}
+	return func() Msg {
+		return batchMsg(validCmds)
+	}
+}
+
+// batchMsg is the internal message used to perform a bunch of commands. You
+// can send a batchMsg with Batch.
+type batchMsg []Cmd
+
+// Sequence runs the given commands one at a time, in order. Contrast this with
+// Batch, which runs commands concurrently.
+func Sequence(cmds ...Cmd) Cmd {
+	return func() Msg {
+		return sequenceMsg(cmds)
+	}
+}
+
+// sequenceMsg is used interally to run the the given commands in order.
+type sequenceMsg []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.