feat(react-email): added a theme switcher to the dev preview

.changeset/dirty-needles-chew.md

@@ -0,0 +1,5 @@
+---
+"react-email": minor
+---
+
+Theme switcher for email template

packages/react-email/src/app/preview/[...slug]/preview.tsx

@@ -1,14 +1,15 @@
 'use client';
 
 import { usePathname, useRouter, useSearchParams } from 'next/navigation';
-import React from 'react';
+import React, { useRef } from 'react';
 import { Toaster } from 'sonner';
 import type { EmailRenderingResult } from '../../../actions/render-email-by-path';
 import { CodeContainer } from '../../../components/code-container';
 import { Shell } from '../../../components/shell';
 import { Tooltip } from '../../../components/tooltip';
 import { useEmailRenderingResult } from '../../../hooks/use-email-rendering-result';
 import { useHotreload } from '../../../hooks/use-hot-reload';
+import { useIframeColorScheme } from '../../../hooks/use-iframe-color-scheme';
 import { useRenderingMetadata } from '../../../hooks/use-rendering-metadata';
 import { RenderingError } from './rendering-error';
 
@@ -29,6 +30,7 @@ const Preview = ({
   const pathname = usePathname();
   const searchParams = useSearchParams();
 
+  const activeTheme = searchParams.get('theme') ?? 'light';
   const activeView = searchParams.get('view') ?? 'desktop';
   const activeLang = searchParams.get('lang') ?? 'jsx';
 
@@ -43,6 +45,9 @@ const Preview = ({
     serverRenderingResult,
   );
 
+  const iframeRef = useRef<HTMLIFrameElement>(null);
+  useIframeColorScheme(iframeRef, activeTheme);
+
   if (process.env.NEXT_PUBLIC_IS_BUILDING !== 'true') {
     // this will not change on runtime so it doesn't violate
     // the rules of hooks
@@ -60,28 +65,20 @@ const Preview = ({
     });
   }
 
-  const handleViewChange = (view: string) => {
-    const params = new URLSearchParams(searchParams);
-    params.set('view', view);
-    router.push(`${pathname}?${params.toString()}`);
-  };
+  const hasNoErrors = typeof renderedEmailMetadata !== 'undefined';
 
-  const handleLangChange = (lang: string) => {
+  const setActiveLang = (lang: string) => {
     const params = new URLSearchParams(searchParams);
     params.set('view', 'source');
     params.set('lang', lang);
     router.push(`${pathname}?${params.toString()}`);
   };
 
-  const hasNoErrors = typeof renderedEmailMetadata !== 'undefined';
-
   return (
     <Shell
-      activeView={hasNoErrors ? activeView : undefined}
       currentEmailOpenSlug={slug}
       markup={renderedEmailMetadata?.markup}
       pathSeparator={pathSeparator}
-      setActiveView={hasNoErrors ? handleViewChange : undefined}
     >
       {/* This relative is so that when there is any error the user can still switch between emails */}
       <div className="relative h-full">
@@ -93,22 +90,24 @@ const Preview = ({
           <>
             {activeView === 'desktop' && (
               <iframe
-                className="w-full bg-white h-[calc(100vh_-_140px)] lg:h-[calc(100vh_-_70px)]"
+                className="h-[calc(100vh_-_140px)] w-full bg-white lg:h-[calc(100vh_-_70px)]"
+                ref={iframeRef}
                 srcDoc={renderedEmailMetadata.markup}
                 title={slug}
               />
             )}
 
             {activeView === 'mobile' && (
               <iframe
-                className="w-[360px] bg-white h-[calc(100vh_-_140px)] lg:h-[calc(100vh_-_70px)] mx-auto"
+                className="mx-auto h-[calc(100vh_-_140px)] w-[360px] bg-white lg:h-[calc(100vh_-_70px)]"
+                ref={iframeRef}
                 srcDoc={renderedEmailMetadata.markup}
                 title={slug}
               />
             )}
 
             {activeView === 'source' && (
-              <div className="flex gap-6 mx-auto p-6 max-w-3xl">
+              <div className="mx-auto flex max-w-3xl gap-6 p-6">
                 <Tooltip.Provider>
                   <CodeContainer
                     activeLang={activeLang}
@@ -126,7 +125,7 @@ const Preview = ({
                         content: renderedEmailMetadata.plainText,
                       },
                     ]}
-                    setActiveLang={handleLangChange}
+                    setActiveLang={setActiveLang}
                   />
                 </Tooltip.Provider>
               </div>

packages/react-email/src/components/icons/icon-moon.tsx

@@ -0,0 +1,16 @@
+import * as React from 'react';
+import type { IconElement, IconProps } from './icon-base';
+import { IconBase } from './icon-base';
+
+export const IconMoon = React.forwardRef<IconElement, Readonly<IconProps>>(
+  ({ ...props }, forwardedRef) => (
+    <IconBase ref={forwardedRef} {...props}>
+      <path
+        fill="currentColor"
+        d="m17.75 4.09l-2.53 1.94l.91 3.06l-2.63-1.81l-2.63 1.81l.91-3.06l-2.53-1.94L12.44 4l1.06-3l1.06 3zm3.5 6.91l-1.64 1.25l.59 1.98l-1.7-1.17l-1.7 1.17l.59-1.98L15.75 11l2.06-.05L18.5 9l.69 1.95zm-2.28 4.95c.83-.08 1.72 1.1 1.19 1.85c-.32.45-.66.87-1.08 1.27C15.17 23 8.84 23 4.94 19.07c-3.91-3.9-3.91-10.24 0-14.14c.4-.4.82-.76 1.27-1.08c.75-.53 1.93.36 1.85 1.19c-.27 2.86.69 5.83 2.89 8.02a9.96 9.96 0 0 0 8.02 2.89m-1.64 2.02a12.08 12.08 0 0 1-7.8-3.47c-2.17-2.19-3.33-5-3.49-7.82c-2.81 3.14-2.7 7.96.31 10.98c3.02 3.01 7.84 3.12 10.98.31"
+      />
+    </IconBase>
+  ),
+);
+
+IconMoon.displayName = 'IconMoon';

packages/react-email/src/components/icons/icon-sun.tsx

@@ -0,0 +1,16 @@
+import * as React from 'react';
+import type { IconElement, IconProps } from './icon-base';
+import { IconBase } from './icon-base';
+
+export const IconSun = React.forwardRef<IconElement, Readonly<IconProps>>(
+  ({ ...props }, forwardedRef) => (
+    <IconBase ref={forwardedRef} {...props}>
+      <path
+        fill="currentColor"
+        d="m3.55 19.09l1.41 1.41l1.8-1.79l-1.42-1.42M12 6c-3.31 0-6 2.69-6 6s2.69 6 6 6s6-2.69 6-6c0-3.32-2.69-6-6-6m8 7h3v-2h-3m-2.76 7.71l1.8 1.79l1.41-1.41l-1.79-1.8M20.45 5l-1.41-1.4l-1.8 1.79l1.42 1.42M13 1h-2v3h2M6.76 5.39L4.96 3.6L3.55 5l1.79 1.81zM1 13h3v-2H1m12 9h-2v3h2"
+      />
+    </IconBase>
+  ),
+);
+
+IconSun.displayName = 'IconSun';

packages/react-email/src/components/shell.tsx

@@ -11,17 +11,13 @@ interface ShellProps extends RootProps {
   markup?: string;
   currentEmailOpenSlug?: string;
   pathSeparator?: string;
-  activeView?: string;
-  setActiveView?: (view: string) => void;
 }
 
 export const Shell = ({
   currentEmailOpenSlug,
   children,
   pathSeparator,
   markup,
-  activeView,
-  setActiveView,
 }: ShellProps) => {
   const [sidebarToggled, setSidebarToggled] = React.useState(false);
   const [triggerTransition, setTriggerTransition] = React.useState(false);
@@ -89,7 +85,6 @@ export const Shell = ({
         >
           {currentEmailOpenSlug && pathSeparator ? (
             <Topbar
-              activeView={activeView}
               currentEmailOpenSlug={currentEmailOpenSlug}
               markup={markup}
               onToggleSidebar={() => {
@@ -104,11 +99,10 @@ export const Shell = ({
                 }, 300);
               }}
               pathSeparator={pathSeparator}
-              setActiveView={setActiveView}
             />
           ) : null}
 
-          <div className="h-[calc(100vh_-_70px)] overflow-auto mx-auto">
+          <div className="h-[calc(100vh_-_70px)] overflow-auto mx-auto ">
             {children}
           </div>
         </main>

packages/react-email/src/components/topbar.tsx

@@ -1,41 +1,58 @@
 'use client';
 import * as ToggleGroup from '@radix-ui/react-toggle-group';
 import { motion } from 'framer-motion';
-import type * as React from 'react';
+import { usePathname, useRouter, useSearchParams } from 'next/navigation';
 import { cn } from '../utils';
 import { tabTransition } from '../utils/constants';
 import { Heading } from './heading';
 import { IconHideSidebar } from './icons/icon-hide-sidebar';
 import { IconMonitor } from './icons/icon-monitor';
+import { IconMoon } from './icons/icon-moon';
 import { IconPhone } from './icons/icon-phone';
 import { IconSource } from './icons/icon-source';
+import { IconSun } from './icons/icon-sun';
 import { Send } from './send';
 import { Tooltip } from './tooltip';
 
 interface TopbarProps {
   currentEmailOpenSlug: string;
   pathSeparator: string;
-  activeView?: string;
   markup?: string;
   onToggleSidebar?: () => void;
-  setActiveView?: (view: string) => void;
 }
 
 export const Topbar: React.FC<Readonly<TopbarProps>> = ({
   currentEmailOpenSlug,
   pathSeparator,
   markup,
-  activeView,
-  setActiveView,
   onToggleSidebar,
 }) => {
+  const router = useRouter();
+  const pathname = usePathname();
+  const searchParams = useSearchParams();
+
+  const activeTheme = searchParams.get('theme') ?? 'light';
+  const activeView = searchParams.get('view') ?? 'desktop';
+
+  const setActiveView = (view: string) => {
+    const params = new URLSearchParams(searchParams);
+    params.set('view', view);
+    router.push(`${pathname}?${params.toString()}`);
+  };
+
+  const setTheme = (theme: string) => {
+    const params = new URLSearchParams(searchParams);
+    params.set('theme', theme);
+    router.push(`${pathname}?${params.toString()}`);
+  };
+
   return (
     <Tooltip.Provider>
-      <header className="flex relative items-center px-4 justify-between h-[70px] border-b border-slate-6">
+      <header className="relative flex h-[70px] items-center justify-between border-slate-6 border-b px-4">
         <Tooltip>
           <Tooltip.Trigger asChild>
             <button
-              className="hidden lg:flex rounded-lg px-2 py-2 transition ease-in-out duration-200 relative hover:bg-slate-5 text-slate-11 hover:text-slate-12"
+              className="relative hidden rounded-lg px-2 py-2 text-slate-11 transition duration-200 ease-in-out hover:bg-slate-5 hover:text-slate-12 lg:flex"
               onClick={() => {
                 if (onToggleSidebar) {
                   onToggleSidebar();
@@ -49,18 +66,87 @@ export const Topbar: React.FC<Readonly<TopbarProps>> = ({
           <Tooltip.Content>Show/hide sidebar</Tooltip.Content>
         </Tooltip>
 
-        <div className="items-center overflow-hidden hidden lg:flex text-center absolute left-1/2 transform -translate-x-1/2 top-1/2 -translate-y-1/2">
+        <div className="-translate-x-1/2 -translate-y-1/2 absolute top-1/2 left-1/2 hidden transform items-center overflow-hidden text-center lg:flex">
           <Heading as="h2" className="truncate" size="2" weight="medium">
             {currentEmailOpenSlug.split(pathSeparator).pop()}
           </Heading>
         </div>
 
-        <div className="flex gap-3 justify-between lg:justify-start w-full lg:w-fit">
+        <div className="flex w-full justify-between gap-3 lg:w-fit lg:justify-start">
+          <ToggleGroup.Root
+            aria-label="Color Scheme"
+            className="inline-block items-center bg-slate-2 border border-slate-6 rounded-md overflow-hidden h-[36px]"
+            id="theme-toggle"
+            onValueChange={(value) => {
+              if (value) setTheme(value);
+            }}
+            type="single"
+            value={activeTheme}
+          >
+            <ToggleGroup.Item value="light">
+              <Tooltip>
+                <Tooltip.Trigger asChild>
+                  <div
+                    className={cn(
+                      'relative px-3 py-2 transition duration-200 ease-in-out hover:text-slate-12',
+                      {
+                        'text-slate-11': activeTheme !== 'light',
+                        'text-slate-12': activeTheme === 'light',
+                      },
+                    )}
+                  >
+                    {activeTheme === 'light' && (
+                      <motion.span
+                        animate={{ opacity: 1 }}
+                        className="absolute top-0 right-0 bottom-0 left-0 bg-slate-4"
+                        exit={{ opacity: 0 }}
+                        initial={{ opacity: 0 }}
+                        layoutId="topbar-theme-tabs"
+                        transition={tabTransition}
+                      />
+                    )}
+                    <IconSun />
+                  </div>
+                </Tooltip.Trigger>
+                <Tooltip.Content>Light</Tooltip.Content>
+              </Tooltip>
+            </ToggleGroup.Item>
+            <ToggleGroup.Item value="dark">
+              <Tooltip>
+                <Tooltip.Trigger asChild>
+                  <div
+                    className={cn(
+                      'relative px-3 py-2 transition duration-200 ease-in-out hover:text-slate-12',
+                      {
+                        'text-slate-11': activeTheme !== 'dark',
+                        'text-slate-12': activeTheme === 'dark',
+                      },
+                    )}
+                  >
+                    {activeTheme === 'dark' && (
+                      <motion.span
+                        animate={{ opacity: 1 }}
+                        className="absolute top-0 right-0 bottom-0 left-0 bg-slate-4"
+                        exit={{ opacity: 0 }}
+                        initial={{ opacity: 0 }}
+                        layoutId="topbar-theme-tabs"
+                        transition={tabTransition}
+                      />
+                    )}
+                    <IconMoon />
+                  </div>
+                </Tooltip.Trigger>
+                <Tooltip.Content>Dark</Tooltip.Content>
+              </Tooltip>
+            </ToggleGroup.Item>
+          </ToggleGroup.Root>
+
           <ToggleGroup.Root
             aria-label="View mode"
             className="inline-block items-center bg-slate-2 border border-slate-6 rounded-md overflow-hidden h-[36px]"
+            id="view-toggle"
             onValueChange={(value) => {
-              if (value) setActiveView?.(value);
+              if (value) setActiveView(value);
             }}
             type="single"
             value={activeView}
@@ -83,7 +169,7 @@ export const Topbar: React.FC<Readonly<TopbarProps>> = ({
                         className="absolute left-0 right-0 top-0 bottom-0 bg-slate-4"
                         exit={{ opacity: 0 }}
                         initial={{ opacity: 0 }}
-                        layoutId="topbar-tabs"
+                        layoutId="topbar-view-tabs"
                         transition={tabTransition}
                       />
                     )}
@@ -111,7 +197,7 @@ export const Topbar: React.FC<Readonly<TopbarProps>> = ({
                         className="absolute left-0 right-0 top-0 bottom-0 bg-slate-4"
                         exit={{ opacity: 0 }}
                         initial={{ opacity: 0 }}
-                        layoutId="topbar-tabs"
+                        layoutId="topbar-view-tabs"
                         transition={tabTransition}
                       />
                     )}
@@ -139,7 +225,7 @@ export const Topbar: React.FC<Readonly<TopbarProps>> = ({
                         className="absolute left-0 right-0 top-0 bottom-0 bg-slate-4"
                         exit={{ opacity: 0 }}
                         initial={{ opacity: 0 }}
-                        layoutId="topbar-tabs"
+                        layoutId="topbar-view-tabs"
                         transition={tabTransition}
                       />
                     )}