From 642621f44c4b3995f1d1db2017860409cfd91eac Mon Sep 17 00:00:00 2001
From: "Grigorii K. Shartsev" <me@shgk.me>
Date: Thu, 19 Jun 2025 17:04:50 +0200
Subject: [PATCH 1/2] chore(frontend): add useAsyncInit helper

Signed-off-by: Grigorii K. Shartsev <me@shgk.me>
---
 src/composables/useAsyncInit.ts | 70 +++++++++++++++++++++++++++++++++
 1 file changed, 70 insertions(+)
 create mode 100644 src/composables/useAsyncInit.ts

diff --git a/src/composables/useAsyncInit.ts b/src/composables/useAsyncInit.ts
new file mode 100644
index 0000000000..3e77d58aa1
--- /dev/null
+++ b/src/composables/useAsyncInit.ts
@@ -0,0 +1,70 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+import type { ShallowRef } from 'vue'
+
+import { shallowReadonly, shallowRef } from 'vue'
+
+type ResultContainer<T> = {
+	result: Readonly<ShallowRef<T | undefined>>
+	isReady: ShallowRef<boolean>
+	isLoading: ShallowRef<boolean>
+	init: () => Promise<void>
+}
+
+/**
+ * Cache modules by loader to immediately return resolved module.
+ * Note: the loader itself is safe to be called multiple times. It is resolved by ESM/Bundler.
+ * But with a promise it requires at least one tick to resolve.
+ */
+const cache = new Map<() => Promise<unknown>, ResultContainer<unknown>>()
+
+/**
+ * Use lazy/async initialization.
+ * Allows to use something requiring asynchronous load/initialization with reactivity, such as dynamically imported modules or heavy initialized modules.
+ * Make sure that the same initiator function reference is used for the same initialization.
+ * @param initiator - Initialization function
+ * @param immediate - Whether to call the initiator immediately
+ */
+export function useAsyncInit<T>(initiator: () => Promise<T>, immediate: boolean = false): ResultContainer<T> {
+	if (cache.has(initiator)) {
+		return cache.get(initiator) as ResultContainer<T>
+	}
+
+	// Use shallowRef to avoid unexpected deep reactivity for the result
+	const result = shallowRef<T | undefined>(undefined)
+	const isReady = shallowRef(false)
+	const isLoading = shallowRef(false)
+
+	/**
+	 * Initialize
+	 */
+	async function init() {
+		// Avoid multiple initializations
+		if (isReady.value || isLoading.value) {
+			return
+		}
+
+		isLoading.value = true
+		result.value = await initiator()
+		isLoading.value = false
+		isReady.value = true
+	}
+
+	const resultContainer: ResultContainer<T> = {
+		result: shallowReadonly(result),
+		isReady: shallowReadonly(isReady),
+		isLoading: shallowReadonly(isLoading),
+		init,
+	}
+
+	cache.set(initiator, resultContainer)
+
+	if (immediate) {
+		init()
+	}
+
+	return resultContainer
+}

From 5e9e68a72ad6a2efb5b2d3c317ebecc397f7919c Mon Sep 17 00:00:00 2001
From: "Grigorii K. Shartsev" <me@shgk.me>
Date: Thu, 19 Jun 2025 17:10:19 +0200
Subject: [PATCH 2/2] perf(frontend): lazy load libphonenumber

Signed-off-by: Grigorii K. Shartsev <me@shgk.me>
---
 src/components/SelectPhoneNumber.vue | 16 ++++++++++----
 src/composables/useLibphonenumber.ts | 33 ++++++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 4 deletions(-)
 create mode 100644 src/composables/useLibphonenumber.ts

diff --git a/src/components/SelectPhoneNumber.vue b/src/components/SelectPhoneNumber.vue
index 79646672d6..9f4eeac8e5 100644
--- a/src/components/SelectPhoneNumber.vue
+++ b/src/components/SelectPhoneNumber.vue
@@ -22,11 +22,11 @@
 
 <script>
 import { t } from '@nextcloud/l10n'
-import { parsePhoneNumberFromString, validatePhoneNumberLength } from 'libphonenumber-js'
 import NcAppNavigationCaption from '@nextcloud/vue/components/NcAppNavigationCaption'
 import NcListItem from '@nextcloud/vue/components/NcListItem'
 import Phone from 'vue-material-design-icons/Phone.vue'
 import Hint from './UIShared/Hint.vue'
+import { useLibphonenumber } from '../composables/useLibphonenumber.ts'
 import { ATTENDEE, AVATAR } from '../constants.ts'
 
 export default {
@@ -59,8 +59,12 @@ export default {
 	emits: ['select', 'update:participantPhoneItem'],
 
 	setup() {
+		const { isLibphonenumberReady, libphonenumber } = useLibphonenumber()
+
 		return {
 			AVATAR,
+			isLibphonenumberReady,
+			libphonenumber,
 		}
 	},
 
@@ -70,13 +74,17 @@ export default {
 		 * @return {import('libphonenumber-js').PhoneNumber|undefined}
 		 */
 		libPhoneNumber() {
-			return this.value
-				? parsePhoneNumberFromString(this.value)
+			return this.isLibphonenumberReady && this.value
+				? this.libphonenumber.parsePhoneNumberFromString(this.value)
 				: undefined
 		},
 
 		errorHint() {
-			switch (validatePhoneNumberLength(this.value)) {
+			if (!this.isLibphonenumberReady) {
+				return t('spreed', 'Loading …')
+			}
+
+			switch (this.libphonenumber.validatePhoneNumberLength(this.value)) {
 				case 'INVALID_LENGTH': return t('spreed', 'Number length is not valid')
 				case 'INVALID_COUNTRY': return t('spreed', 'Region code is not valid')
 				case 'TOO_SHORT': return t('spreed', 'Number length is too short')
diff --git a/src/composables/useLibphonenumber.ts b/src/composables/useLibphonenumber.ts
new file mode 100644
index 0000000000..dc4bb15f0d
--- /dev/null
+++ b/src/composables/useLibphonenumber.ts
@@ -0,0 +1,33 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+
+import { useAsyncInit } from './useAsyncInit.ts'
+
+/**
+ * Dynamically import libphonenumber-js module
+ */
+async function loadLibphonenumber() {
+	// Destructure immediately to help bundlers to tree-shake unused parts
+	const { parsePhoneNumberFromString, validatePhoneNumberLength } = await import('libphonenumber-js')
+	return {
+		parsePhoneNumberFromString,
+		validatePhoneNumberLength,
+	}
+}
+
+/**
+ * Use libphonenumber-js asynchronously loaded module
+ */
+export function useLibphonenumber() {
+	const {
+		isReady: isLibphonenumberReady,
+		result: libphonenumber,
+	} = useAsyncInit(loadLibphonenumber, true)
+
+	return {
+		isLibphonenumberReady,
+		libphonenumber,
+	}
+}