From ad220fdb95b524b451e11bfcddd1f86e768e007d Mon Sep 17 00:00:00 2001
From: Maxwell Barvian <max@barvian.me>
Date: Wed, 13 Nov 2024 05:55:09 -0800
Subject: [PATCH] Add <NumberFlowGroup> for Vue

---
 .changeset/thin-hotels-chew.md                |  5 +++
 packages/vue/src/NumberFlowGroup.vue          | 38 +++++++++++++++++++
 packages/vue/src/group.ts                     |  9 +++++
 packages/vue/src/index.ts                     |  2 +
 packages/vue/src/index.vue                    | 29 ++++----------
 .../examples/_Group/vue/Component.vue         | 22 +++++++----
 site/src/pages/[...framework]/index.mdx       | 14 +++++++
 7 files changed, 90 insertions(+), 29 deletions(-)
 create mode 100644 .changeset/thin-hotels-chew.md
 create mode 100644 packages/vue/src/NumberFlowGroup.vue
 create mode 100644 packages/vue/src/group.ts

diff --git a/.changeset/thin-hotels-chew.md b/.changeset/thin-hotels-chew.md
new file mode 100644
index 00000000..69974f76
--- /dev/null
+++ b/.changeset/thin-hotels-chew.md
@@ -0,0 +1,5 @@
+---
+'@number-flow/vue': patch
+---
+
+Add <NumberFlowGroup>
diff --git a/packages/vue/src/NumberFlowGroup.vue b/packages/vue/src/NumberFlowGroup.vue
new file mode 100644
index 00000000..5c5c1580
--- /dev/null
+++ b/packages/vue/src/NumberFlowGroup.vue
@@ -0,0 +1,38 @@
+<script lang="ts" setup>
+import type { NumberFlowLite } from 'number-flow'
+import { key, type RegisterWithGroup } from './group'
+import { provide, watch, type Ref, nextTick, onUnmounted } from 'vue'
+
+const flows = new Set<Ref<NumberFlowLite | undefined>>()
+let updating = false
+
+const registerWithGroup: RegisterWithGroup = (el, parts) => {
+	flows.add(el)
+
+	watch(
+		parts,
+		async () => {
+			if (updating) return
+			updating = true
+			flows.forEach((flow) => {
+				flow.value?.willUpdate()
+			})
+			await nextTick()
+			flows.forEach((flow) => {
+				flow.value?.didUpdate()
+			})
+			updating = false
+		}
+		// { flush: 'pre' } // default
+	)
+
+	onUnmounted(() => {
+		flows.delete(el)
+	})
+}
+
+provide(key, registerWithGroup)
+</script>
+<template>
+	<slot />
+</template>
diff --git a/packages/vue/src/group.ts b/packages/vue/src/group.ts
new file mode 100644
index 00000000..5159be24
--- /dev/null
+++ b/packages/vue/src/group.ts
@@ -0,0 +1,9 @@
+import type { NumberFlowLite, partitionParts } from 'number-flow'
+import type { InjectionKey, Ref, ComputedRef, MaybeRefOrGetter } from 'vue'
+
+export type RegisterWithGroup = (
+	el: Ref<NumberFlowLite | undefined>,
+	parts: ComputedRef<ReturnType<typeof partitionParts>>
+) => void
+
+export const key = Symbol() as InjectionKey<RegisterWithGroup | undefined>
diff --git a/packages/vue/src/index.ts b/packages/vue/src/index.ts
index e3567b96..09d96b5d 100644
--- a/packages/vue/src/index.ts
+++ b/packages/vue/src/index.ts
@@ -6,6 +6,8 @@ import {
 	prefersReducedMotion
 } from 'number-flow'
 
+export { default as NumberFlowGroup } from './NumberFlowGroup.vue'
+
 export type { Value, Format, Trend } from 'number-flow'
 export { NumberFlowElement }
 
diff --git a/packages/vue/src/index.vue b/packages/vue/src/index.vue
index 46fd2620..38fada08 100644
--- a/packages/vue/src/index.vue
+++ b/packages/vue/src/index.vue
@@ -7,7 +7,8 @@ import {
 	NumberFlowLite,
 	type Props as NumberFlowProps
 } from 'number-flow'
-import { computed, ref } from 'vue'
+import { computed, inject, ref, watch } from 'vue'
+import { key as groupKey } from './group'
 
 type Props = Partial<NumberFlowProps> & {
 	locales?: Intl.LocalesArgument
@@ -18,7 +19,7 @@ type Props = Partial<NumberFlowProps> & {
 
 // This is repetitive but I couldn't get it any cleaner using `withDefaults`,
 // because then you can't destructure,
-// and if you don't set defaults Vue will use its own for i.e. booleans.
+// and if you don't set defaults Vue will use its own for e.g. booleans.
 const {
 	locales,
 	format,
@@ -41,7 +42,6 @@ defineOptions({
 	inheritAttrs: false // set them manually to ensure `parts` updates last
 })
 
-// Technically the original animationsstart still emits but ah well:
 const emit = defineEmits<{
 	(e: 'animationsstart'): void
 	(e: 'animationsfinish'): void
@@ -50,32 +50,19 @@ const emit = defineEmits<{
 // You're supposed to cache these between uses:
 // https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Number/toLocaleString
 const formatter = computed(() => new Intl.NumberFormat(locales, format))
-
 const parts = computed(() => partitionParts(value, formatter.value))
 
-// Pre effects don't seem to batch to handle grouping like React:
-// https://discord.com/channels/325477692906536972/1299071468533055541
-//
-// watch(
-// 	[parts, () => isolate],
-// 	([_, isolate]) => {
-// 		if (!isolate) el.value?.willUpdate()
-// 	},
-// 	{ flush: 'pre' }
-// )
-// watch(
-// 	[parts, () => isolate],
-// 	([_, isolate]) => {
-// 		if (!isolate) el.value?.didUpdate()
-// 	},
-// 	{ flush: 'post' }
-// )
+// Handle grouping. Keep as much logic in NumberFlowGroup.vue as possible
+// for better tree-shaking:
+const register = inject(groupKey, undefined)
+register?.(el, parts)
 </script>
 <template>
 	<!-- Make sure parts is set last: -->
 	<number-flow-vue
 		ref="el"
 		v-bind="$attrs"
+		:manual="Boolean(register)"
 		:trend
 		:continuous
 		:animated
diff --git a/site/src/pages/[...framework]/examples/_Group/vue/Component.vue b/site/src/pages/[...framework]/examples/_Group/vue/Component.vue
index a4f95178..430c8008 100644
--- a/site/src/pages/[...framework]/examples/_Group/vue/Component.vue
+++ b/site/src/pages/[...framework]/examples/_Group/vue/Component.vue
@@ -1,5 +1,5 @@
 <script setup lang="ts">
-import NumberFlow from '@number-flow/vue'
+import NumberFlow, { NumberFlowGroup } from '@number-flow/vue'
 const { value, diff } = defineProps<{
 	value: number
 	diff: number
@@ -7,11 +7,17 @@ const { value, diff } = defineProps<{
 </script>
 
 <template>
-	<div
-		style="--number-flow-char-height: 0.85em"
-		class="~text-xl/4xl flex items-center gap-2 font-semibold"
-	>
-		<NumberFlow :value :format="{ style: 'currency', currency: 'USD' }" />
-		<NumberFlow :value="diff" :format="{ style: 'percent', maximumFractionDigits: 2 }" />
-	</div>
+	<NumberFlowGroup>
+		<div style="--number-flow-char-height: 0.85em" class="flex items-center gap-4 font-semibold">
+			<NumberFlow :value :format="{ style: 'currency', currency: 'USD' }" class="~text-2xl/4xl" />
+			<NumberFlow
+				:value="diff"
+				:format="{ style: 'percent', maximumFractionDigits: 2, signDisplay: 'always' }"
+				:class="[
+					'~text-lg/2xl transition-colors duration-300',
+					diff < 0 ? 'text-red-500' : 'text-emerald-500'
+				]"
+			/>
+		</div>
+	</NumberFlowGroup>
 </template>
diff --git a/site/src/pages/[...framework]/index.mdx b/site/src/pages/[...framework]/index.mdx
index 85df5363..27e6e9b1 100644
--- a/site/src/pages/[...framework]/index.mdx
+++ b/site/src/pages/[...framework]/index.mdx
@@ -16,6 +16,7 @@ import Type from '@/components/Type.astro'
 import Heading from '@/components/Heading.astro'
 import Union from '@/components/Union.astro'
 import Link from '@/components/Link.astro'
+import Group from './examples/_Group/index.astro'
 export { getStaticPaths } from '@/lib/framework'
 export const components = {a: Link, pre: Pre}
 
@@ -271,6 +272,19 @@ See [MDN](https://developer.mozilla.org/en-US/docs/Web/CSS/font-variant-numeric#
 
 {/* <TabularNumsDemo client:visible /> */}
 
+<Match vue svelte>
+---
+
+<Heading value="Grouping"/>
+
+If you're using multiple `<NumberFlow>` components on one line, you can wrap
+them in a `<NumberFlowGroup>` to properly sync their transitions:
+
+<Group />
+
+`<NumberFlowGroup>` doesn't render an element or accept any props.
+</Match>
+
 ---
 
 <Match>