feat: add loading state to Button component and integrate with form submissions

app/components/ui/button.tsx

@@ -1,4 +1,4 @@
-import { Slot } from '@radix-ui/react-slot'
+import { Slot, Slottable } from '@radix-ui/react-slot'
 import { cva, type VariantProps } from 'class-variance-authority'
 import type * as React from 'react'
 
@@ -26,10 +26,14 @@ const buttonVariants = cva(
         lg: 'h-10 rounded-md px-6 has-[>svg]:px-4',
         icon: 'size-9',
       },
+      isLoading: {
+        true: 'cursor-progress',
+      },
     },
     defaultVariants: {
       variant: 'default',
       size: 'default',
+      isLoading: false,
     },
   },
 )
@@ -39,19 +43,27 @@ function Button({
   variant,
   size,
   asChild = false,
+  isLoading = false,
+  children,
   ...props
 }: React.ComponentProps<'button'> &
   VariantProps<typeof buttonVariants> & {
     asChild?: boolean
+    isLoading?: boolean
   }) {
   const Comp = asChild ? Slot : 'button'
 
   return (
     <Comp
       data-slot="button"
-      className={cn(buttonVariants({ variant, size, className }))}
+      className={cn(buttonVariants({ variant, size, isLoading, className }))}
       {...props}
-    />
+    >
+      {isLoading && (
+        <span className="border-background mr-2 h-4 w-4 animate-spin rounded-full border-2 border-t-transparent" />
+      )}
+      <Slottable>{children}</Slottable>
+    </Comp>
   )
 }
 

app/routes/$handle+/posts.$id.edit/route.tsx

@@ -6,7 +6,7 @@ import {
 } from '@conform-to/react'
 import { parseWithZod } from '@conform-to/zod'
 import { ArrowLeftIcon } from 'lucide-react'
-import { data, Form, href, Link, redirect } from 'react-router'
+import { data, Form, href, Link, redirect, useNavigation } from 'react-router'
 import { z } from 'zod'
 import { AppHeadingSection } from '~/components/AppHeadingSection'
 import { Button, Input, Label, Textarea } from '~/components/ui'
@@ -95,6 +95,7 @@ export default function PostEditPage({
     shouldValidate: 'onInput',
     onValidate: ({ formData }) => parseWithZod(formData, { schema }),
   })
+  const navigation = useNavigation()
 
   return (
     <div className="relative">
@@ -130,6 +131,7 @@ export default function PostEditPage({
           name="intent"
           value="update"
           form={form.id}
+          isLoading={navigation.state === 'submitting'}
         >
           更新する
         </Button>

app/routes/auth+/sign_in/route.tsx

@@ -35,7 +35,11 @@ const SignInForm = () => {
   return (
     <div className="mx-auto text-center">
       <fetcher.Form method="POST" action={href('/auth/sign_in')}>
-        <Button type="submit" className="rounded-full">
+        <Button
+          type="submit"
+          className="rounded-full"
+          isLoading={fetcher.state !== 'idle'}
+        >
           Google アカウントでサインイン
         </Button>
       </fetcher.Form>