From eee497f22a3d738e954a83052bcd24c3bdfd6c17 Mon Sep 17 00:00:00 2001
From: Elias Naur <mail@eliasnaur.com>
Date: Fri, 2 Aug 2019 09:04:00 +0200
Subject: [PATCH] ui/app: (wasm) create and add container div if one is not
 provided

Signed-off-by: Elias Naur <mail@eliasnaur.com>
---
 ui/app/os_js.go | 20 +++++++++++++-------
 1 file changed, 13 insertions(+), 7 deletions(-)

diff --git a/ui/app/os_js.go b/ui/app/os_js.go
index 0b5fe9ae..6771336a 100644
--- a/ui/app/os_js.go
+++ b/ui/app/os_js.go
@@ -1,7 +1,6 @@
 package app
 
 import (
-	"errors"
 	"image"
 	"sync"
 	"syscall/js"
@@ -32,14 +31,11 @@ var mainDone = make(chan struct{})
 
 func createWindow(win *Window, opts *WindowOptions) error {
 	doc := js.Global().Get("document")
-	parent := doc.Call("getElementById", "giowindow")
-	if parent == js.Null() {
-		return errors.New("app: #giowindow not found")
-	}
+	cont := getContainer(doc)
 	cnv := createCanvas(doc)
-	parent.Call("appendChild", cnv)
+	cont.Call("appendChild", cnv)
 	tarea := createTextArea(doc)
-	parent.Call("appendChild", tarea)
+	cont.Call("appendChild", tarea)
 	w := &window{
 		cnv:    cnv,
 		tarea:  tarea,
@@ -64,6 +60,16 @@ func createWindow(win *Window, opts *WindowOptions) error {
 	return nil
 }
 
+func getContainer(doc js.Value) js.Value {
+	cont := doc.Call("getElementById", "giowindow")
+	if cont != js.Null() {
+		return cont
+	}
+	cont = doc.Call("createElement", "DIV")
+	doc.Get("body").Call("appendChild", cont)
+	return cont
+}
+
 func createTextArea(doc js.Value) js.Value {
 	tarea := doc.Call("createElement", "input")
 	style := tarea.Get("style")