From 9a06319ff1132013f212e00524ca006e2cce91ac Mon Sep 17 00:00:00 2001
From: Carlos Alexandro Becker <caarlos0@users.noreply.github.com>
Date: Thu, 3 Feb 2022 12:08:34 -0300
Subject: [PATCH] feat: tea.Batch returns nil if all cmds are nil (#217)

Signed-off-by: Carlos A Becker <caarlos0@gmail.com>
---
 commands_test.go | 25 +++++++++++++++++++++++++
 tea.go           | 11 +++++++++--
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/commands_test.go b/commands_test.go
index 749c6a9..e0d5ff3 100644
--- a/commands_test.go
+++ b/commands_test.go
@@ -80,3 +80,28 @@ func TestSequentially(t *testing.T) {
 		})
 	}
 }
+
+func TestBatch(t *testing.T) {
+	t.Run("nil cmd", func(t *testing.T) {
+		if b := Batch(nil); b != nil {
+			t.Fatalf("expected nil, got %+v", b)
+		}
+	})
+	t.Run("empty cmd", func(t *testing.T) {
+		if b := Batch(); b != nil {
+			t.Fatalf("expected nil, got %+v", b)
+		}
+	})
+	t.Run("single cmd", func(t *testing.T) {
+		b := Batch(Quit)()
+		if l := len(b.(batchMsg)); l != 1 {
+			t.Fatalf("expected a []Cmd with len 1, got %d", l)
+		}
+	})
+	t.Run("mixed nil cmds", func(t *testing.T) {
+		b := Batch(nil, Quit, nil, Quit, nil, nil)()
+		if l := len(b.(batchMsg)); l != 2 {
+			t.Fatalf("expected a []Cmd with len 2, got %d", l)
+		}
+	})
+}
diff --git a/tea.go b/tea.go
index fdf29ee..ee1bd92 100644
--- a/tea.go
+++ b/tea.go
@@ -119,11 +119,18 @@ type Program struct {
 //     }
 //
 func Batch(cmds ...Cmd) Cmd {
-	if len(cmds) == 0 {
+	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(cmds)
+		return batchMsg(validCmds)
 	}
 }