Add 'Every' subscription for ticking with the system clock

examples/fullscreen/main.go

@@ -55,10 +55,7 @@ func update(message tea.Msg, mdl tea.Model) (tea.Model, tea.Cmd) {
 
 func subscriptions(_ tea.Model) tea.Subs {
 	return tea.Subs{
-		"tick": func() tea.Msg {
-			time.Sleep(time.Second)
-			return tickMsg{}
-		},
+		"tick": tea.Every(time.Second, tickMsg{}),
 	}
 }
 

examples/simple/main.go

@@ -39,6 +39,8 @@ func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
 	m, _ := model.(Model)
 
 	switch msg.(type) {
+	case tea.KeyMsg:
+		return m, tea.Quit
 	case TickMsg:
 		m -= 1
 		if m <= 0 {
@@ -52,16 +54,13 @@ func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {
 // to the terminal.
 func view(model tea.Model) string {
 	m, _ := model.(Model)
-	return fmt.Sprintf("Hi. This program will exit in %d seconds...", m)
+	return fmt.Sprintf("Hi. This program will exit in %d seconds. To quit sooner press any key.", m)
 }
 
 // This is a subscription which we setup in NewProgram(). It waits for one
 // second, sends a tick, and then restarts.
 func subscriptions(_ tea.Model) tea.Subs {
 	return tea.Subs{
-		"tick": func() tea.Msg {
-			time.Sleep(time.Second)
-			return TickMsg{}
-		},
+		"tick": tea.Every(time.Second, TickMsg{}),
 	}
 }

examples/views/main.go

@@ -50,24 +50,14 @@ func subscriptions(model tea.Model) tea.Subs {
 	m, _ := model.(Model)
 	if !m.Chosen || m.Loaded {
 		return tea.Subs{
-			"tick": tick,
+			"tick": tea.Every(time.Second, tickMsg{}),
 		}
 	}
 	return tea.Subs{
-		"frame": frame,
+		"frame": tea.Every(time.Second/60, frameMsg{}),
 	}
 }
 
-func tick() tea.Msg {
-	time.Sleep(time.Second)
-	return tickMsg{}
-}
-
-func frame() tea.Msg {
-	time.Sleep(time.Second / 60)
-	return frameMsg{}
-}
-
 // UPDATES
 
 func update(msg tea.Msg, model tea.Model) (tea.Model, tea.Cmd) {

subscriptions.go

@@ -0,0 +1,21 @@
+package tea
+
+import (
+	"time"
+)
+
+// Every is a subscription that ticks with the system clock at the given
+// duration
+//
+// TODO: make it cancelable
+func Every(duration time.Duration, msg Msg) Sub {
+	return func() Msg {
+		n := time.Now()
+		d := n.Truncate(duration).Add(duration).Sub(n)
+		t := time.NewTimer(d)
+		select {
+		case <-t.C:
+			return msg
+		}
+	}
+}