Building Vhisper: Voice Notes App with AI Transcription and Post-Processing
A Step-by-Step Guide to Building a Voice Notes App with Nuxt, NuxtHub, and Cloudflare's Workers AI, D1, and R2
After wrapping up my last project—a chat interface to search GitHub—I found myself searching for the next idea to tackle. As a developer, inspiration often comes unexpectedly, and this time, it struck while scrolling through my GitHub feed. A repo, starred by Daniel Roe (Nuxt Core Team Lead), caught my eye. It was an Electron-based voice notes app designed for macOS.
Something about the simplicity of voice notes combined with the technical challenge intrigued me. Could I take this concept further? Could I build a modern, AI-powered voice notes app using web technologies? That urge to build led me here, to this blog post, where I’ll walk you through building Vhisper, a voice notes app with AI transcription and post-processing, built with the Nuxt ecosystem and powered by Cloudflare.
And before you say it, I must make a confession: “Hi! My name is Rajeev, and I am addicted to talking/chatting.”.
Project Overview
Now that the formalities are done, let’s focus on what we’ll be building in this project. The goal is to create Vhisper, a web-based voice notes application with the following core features:
Recording Voice Notes: Users can record voice notes directly in the browser.
AI-Powered Transcription: Each recording is processed via Cloudflare Workers AI, converting speech to text.
Post-Processing with Custom Prompts: Users can customize how transcriptions are refined using an AI-driven post-processing step.
Seamless Data Management (CRUD): Notes and audio files are efficiently stored using Cloudflare’s D1 database and R2 storage.
To give you a better sense of what we’re aiming for, here’s a quick demo showcasing Vhisper’s main features:
You can experience it live here: https://vhisper.nuxt.dev
By the end of this guide, you’ll know exactly how to build and deploy this voice notes app using Nuxt, NuxtHub and Cloudflare services—a stack that combines innovation with developer-first simplicity. Ready to build it? Let’s get started!
Project Setup
Before setting up the project let’s review the technologies used to build this app:
Nuxt: Vue.js framework for the application foundation
Nuxt UI (v3): For creating a polished and professional frontend
Drizzle: Database ORM
Zod: For client/server side data validation
NuxtHub: Backend (
database
,storage
,AI
etc.), deployment and administration platform for NuxtCloudflare: Powers NuxtHub to provide various services
Prerequisites
To follow along, apart from basic necessities like Node.js, npm, and some Nuxt knowledge, you’ll need:
A Cloudflare account to use Workers AI and deploy your project. If you don’t have one, you can set it up here.
A NuxtHub Admin Account for managing apps via the NuxtHub dashboard. Sign up here.
Project Init
We’ll start with the NuxtHub starter template. Run the following command to create and navigate to your new project directory:
# Create project and change into the project dir
npx nuxthub init voice-notes && cd $_
If you plan to use pnpm as your package manager, add a .npmrc
file at the root of your project with this line to hoist dependencies:
# .npmrc
shamefully-hoist=true
Now, install the dependencies:
Nuxt modules:
pnpm add @nuxt/ui@next
Drizzle and related tools:
pnpm add drizzle-orm drizzle-zod @vueuse/core
Icon packs:
pnpm add @iconify-json/lucide @iconify-json/simple-icons
Dev dependencies:
pnpm add -D drizzle-kit
Update your nuxt.config.ts
file as follows:
export default defineNuxtConfig({
modules: ["@nuxthub/core", "@nuxt/eslint", "nuxt-auth-utils", "@nuxt/ui"],
devtools: { enabled: true },
runtimeConfig: {
public: {
helloText: "Hello from the Edge 👋",
},
},
future: { compatibilityVersion: 4 },
compatibilityDate: "2024-07-30",
hub: {
ai: true,
blob: true,
database: true,
},
css: ["~/assets/css/main.css"],
eslint: {
config: {
stylistic: false,
},
},
});
We’ve made the following changes to the Nuxt config file:
Updated the Nuxt modules used in the app
Enabled required NuxtHub features
And, added the
main.css
file path.
Create the main.css
file in the app/assets/css
folder with this content:
@import "tailwindcss";
@import "@nuxt/ui";
Testing the Setup
Run the development server:
pnpm dev
Visit http://localhost:3000
in your browser. If everything is set up correctly, you’ll see the message: “Hello from the Edge 👋” with a refresh button.
node_modules
and pnpm-lock.yaml
, and then run pnpm install
to re-install the dependecies.Building the Basic Backend
With the project setup complete, let’s dive into building the backend. We’ll begin by creating API endpoints to handle core functionalities, followed by configuring the database and integrating validation.
But before jumping to code, let’s understand how you’ll interact with various Cloudflare offerings. If you’ve been attentive, you should know the answer, NuxrHub, but what is NuxtHub?
What is NuxtHub?
NuxtHub is a developer-friendly interface built on top of Cloudflare’s robust services. It simplifies the process of creating, binding, and managing services for your project, offering a seamless development experience (DX).
You started with a NuxtHub template, so the project comes preconfigured with the @nuxthub/core
module. During the setup, you also enabled the required Cloudflare services: AI, Database, and Blob. The NuxtHub core module exposes these services through interfaces prefixed with hub
. For example, hubAI
is used for AI features, hubBlob
for object storage, and so on.
Time is ripe now to work on the first API endpoint.
/api/transcribe
Endpoint
Create a new file named transcribe.post.ts
inside the server/api
directory, and add the following code to it:
// server/api/transcribe.post.ts
export default defineEventHandler(async (event) => {
const form = await readFormData(event);
const blob = form.get("audio") as Blob;
if (!blob) {
throw createError({
statusCode: 400,
message: "Missing audio blob to transcribe",
});
}
ensureBlob(blob, { maxSize: "8MB", types: ["audio"] });
try {
const response = await hubAI().run("@cf/openai/whisper", {
audio: [...new Uint8Array(await blob.arrayBuffer())],
});
return response.text;
} catch (err) {
console.error("Error transcribing audio:", err);
throw createError({
statusCode: 500,
message: "Failed to transcribe audio. Please try again.",
});
}
});
The above code does the following:
Parses incoming form data to extract the audio as a
Blob
Verifies that it’s an audio blob and is less than
8MB
in size using a@nuxthub/core
utility functionensureBlob
Passes on the array buffer to the
Whisper
model throughhubAI
for transcriptionReturns the transcribed text to the client
Before you can use Workers AI in development, you’ll need to link it to your Cloudflare project. As we’re using NuxtHub as the interface, running the following command will create/link a new or existing NuxtHub project with this project.
npx nuxthub link
/api/upload
Endpoint
Next, create an endpoint to upload the audio recordings to the R2 storage. Create a new file upload.put.ts
in your /server/api
folder and add the following code to it:
// server/api/upload.put.ts
export default defineEventHandler(async (event) => {
return hubBlob().handleUpload(event, {
formKey: "files",
multiple: true,
ensure: {
maxSize: "8MB",
types: ["audio"],
},
put: {
addRandomSuffix: true,
prefix: "recordings",
},
});
});
The above code uses another utility method from the NuxtHub core module to upload the incoming audio files to R2. handleUpload
does the following:
Looks for the
files
key in the incoming form data to extract blob dataSupports multiple files per event
Ensures that the files are audio and under
8MB
in sizeAnd, finally uploads them to your R2 bucket inside
recordings
folder while also adding a random suffix to the final namesReturns a promise to the client that resolves once all the files are uploaded
Now we just need /notes
endpoints to create & fetch notes entries before the basic backend is done. But to do that we need to create the needed tables. Let’s tackle this in next section.
Defining the notes
Table Schema
As we will use drizzle
to manage and interact with the database, we need to configure it first. Create a new file drizzle.config.ts
in the project root, and add the following to it:
// drizzle.config.ts
import { defineConfig } from 'drizzle-kit';
export default defineConfig({
dialect: 'sqlite',
schema: './server/database/schema.ts',
out: './server/database/migrations',
});
The config above mentions where the database schema is located, and where should the database migrations be generated. The database dialect is set to sqlite
as that is what Cloudflare’s D1 database supports.
Next, create a new file schema.ts
in the server/database
folder, and add the following to it:
// server/database/schema.ts
import crypto from "node:crypto";
import { sql } from "drizzle-orm";
import { sqliteTable, text } from "drizzle-orm/sqlite-core";
export const notes = sqliteTable("notes", {
id: text("id")
.primaryKey()
.$defaultFn(() => "nt_" + crypto.randomBytes(12).toString("hex")),
text: text("text").notNull(),
createdAt: text("created_at")
.notNull()
.default(sql`(CURRENT_TIMESTAMP)`),
updatedAt: text("updated_at")
.notNull()
.default(sql`(CURRENT_TIMESTAMP)`)
.$onUpdate(() => sql`(CURRENT_TIMESTAMP)`),
audioUrls: text("audio_urls", { mode: "json" }).$type<string[]>(),
});
The notes
table schema is straightforward. It includes the note text and optional audio recording URLs stored as a JSON string array.
Finally, create a new file drizzle.ts
in the server/utils
folder, and add the following to it:
// server/utils/drizzle.ts
import { drizzle } from "drizzle-orm/d1";
import * as schema from "../database/schema";
export { sql, eq, and, or, desc } from "drizzle-orm";
export const tables = schema;
export function useDrizzle() {
return drizzle(hubDatabase(), { schema });
}
Here we hook up hubDatabase
with the tables schema through drizzle
and export the server composable useDrizzle
along with the needed operators.
Now we are ready to create the /api/notes
endpoints which we will be doing in the next section.
/api/notes
Endpoints
Create two new files index.post.ts
and index.get.ts
in the server/api/notes
folder and add the respective codes to them as shown below.
// server/api/notes/index.post.ts
import { noteSchema } from "#shared/schemas/note.schema";
export default defineEventHandler(async (event) => {
const { user } = await requireUserSession(event);
const { text, audioUrls } = await readValidatedBody(event, noteSchema.parse);
try {
await useDrizzle()
.insert(tables.notes)
.values({
text,
audioUrls: audioUrls ? audioUrls.map((url) => `/audio/${url}`) : null,
});
return setResponseStatus(event, 201);
} catch (err) {
console.error("Error creating note:", err);
throw createError({
statusCode: 500,
message: "Failed to create note. Please try again.",
});
}
});
The above code reads the validated event body, and creates a new note entry in the database using the drizzle composable we created earlier. We will get to the validation part in a bit.
index.get.ts
// server/api/notes/index.get.ts
export default defineEventHandler(async (event) => {
try {
const notes = await useDrizzle()
.select()
.from(tables.notes)
.orderBy(desc(tables.notes.updatedAt));
return notes;
} catch (err) {
console.error("Error retrieving note:", err);
throw createError({
statusCode: 500,
message: "Failed to get notes. Please try again.",
});
}
});
Here we fetch the notes entries from the table in descending order of updatedAt
field.
Incoming data validation
As mentioned in the beginning, we’ll use Zod
for data validation. Here is the relevant code from index.post.ts
that validates the incoming client data.
const { text, audioUrls } = await readValidatedBody(event, noteSchema.parse);
Create a new file note.schema.ts
in the shared/schemas
folder in the project root directory with the following content:
// shared/schemas/note.schema.ts
import { createInsertSchema, createSelectSchema } from "drizzle-zod";
import { z } from "zod";
import { notes } from "~~/server/database/schema";
export const noteSchema = createInsertSchema(notes, {
text: (schema) =>
schema.text
.min(3, "Note must be at least 3 characters long")
.max(5000, "Note cannot exceed 5000 characters"),
audioUrls: z.string().array().optional(),
}).pick({
text: true,
audioUrls: true,
});
export const noteSelectSchema = createSelectSchema(notes, {
audioUrls: z.string().array().optional(),
});
The above code uses the drizzle-zod
plugin to create the zod
schema needed for validation (The above validation error messages are more suitable for the client side. Feel free to adapt these validation rules to suit your specific project requirements.).
Creating DB Migrations
With the table schema and API endpoints defined, the final step is to create and apply database migrations to bring everything together. Add the following command to your package.json
's scripts:
// ..
"scripts": {
// ..
"db:generate": "drizzle-kit generate"
}
// ..
Next, run pnpm run db:generate
to create the database migrations. These migrations are auto applied by NuxtHub when you run or deploy your project. You can test it by running pnpm dev
and checking the Nuxt Dev Tools as shown below (this is a local sqlite database that is used in the dev mode).
We are done with the basic backend of the project. In the next section, we will code the frontend components and pages to complete the whole thing,
Creating the Basic Frontend
We’ll start with the most important feature first: recording the user voice, and then we’ll move on to creating the needed components and pages.
useMediaRecorder
Composable
Let’s create a composable to handle the media recording functionality. Create a new file useMediaRecorder.ts
in your app/composables
folder and add the following code to it:
// app/composables/useMediaRecorder.ts
interface MediaRecorderState {
isRecording: boolean;
recordingDuration: number;
audioData: Uint8Array | null;
updateTrigger: number;
}
const getSupportedMimeType = () => {
const types = [
"audio/mp4",
"audio/mp4;codecs=mp4a",
"audio/mpeg",
"audio/webm;codecs=opus",
"audio/webm",
];
return (
types.find((type) => MediaRecorder.isTypeSupported(type)) || "audio/webm"
);
};
export function useMediaRecorder() {
const state = ref<MediaRecorderState>({
isRecording: false,
recordingDuration: 0,
audioData: null,
updateTrigger: 0,
});
let mediaRecorder: MediaRecorder | null = null;
let audioContext: AudioContext | null = null;
let analyser: AnalyserNode | null = null;
let animationFrame: number | null = null;
let audioChunks: Blob[] | undefined = undefined;
const updateAudioData = () => {
if (!analyser || !state.value.isRecording || !state.value.audioData) {
if (animationFrame) {
cancelAnimationFrame(animationFrame);
animationFrame = null;
}
return;
}
analyser.getByteTimeDomainData(state.value.audioData);
state.value.updateTrigger += 1;
animationFrame = requestAnimationFrame(updateAudioData);
};
const startRecording = async () => {
try {
const stream = await navigator.mediaDevices.getUserMedia({ audio: true });
audioContext = new AudioContext();
analyser = audioContext.createAnalyser();
const source = audioContext.createMediaStreamSource(stream);
source.connect(analyser);
const options = {
mimeType: getSupportedMimeType(),
audioBitsPerSecond: 64000,
};
mediaRecorder = new MediaRecorder(stream, options);
audioChunks = [];
mediaRecorder.ondataavailable = (e: BlobEvent) => {
audioChunks?.push(e.data);
state.value.recordingDuration += 1;
};
state.value.audioData = new Uint8Array(analyser.frequencyBinCount);
state.value.isRecording = true;
state.value.recordingDuration = 0;
state.value.updateTrigger = 0;
mediaRecorder.start(1000);
updateAudioData();
} catch (err) {
console.error("Error accessing microphone:", err);
throw err;
}
};
const stopRecording = async () => {
return await new Promise<Blob>((resolve) => {
if (mediaRecorder && state.value.isRecording) {
const mimeType = mediaRecorder.mimeType;
mediaRecorder.onstop = () => {
const blob = new Blob(audioChunks, { type: mimeType });
audioChunks = undefined;
state.value.recordingDuration = 0;
state.value.updateTrigger = 0;
state.value.audioData = null;
resolve(blob);
};
state.value.isRecording = false;
mediaRecorder.stop();
mediaRecorder.stream.getTracks().forEach((track) => track.stop());
if (animationFrame) {
cancelAnimationFrame(animationFrame);
animationFrame = null;
}
audioContext?.close();
audioContext = null;
}
});
};
onUnmounted(() => {
stopRecording();
});
return {
state: readonly(state),
startRecording,
stopRecording,
};
}
The above code does the following:
Exposes recording start/stop functionality along with the current recording readonly state
Captures user’s voice using the
MediaRecorder
API whenstartRecording
function is invoked. TheMediaRecorder
API is a simple and efficient way to handle media capture in modern browsers, making it ideal for our use case.Captures audio visualization data using
AudioContext
andAnalyserNode
and updates it in real-time using animation framesCleans up resources and returns the captured audio as a
Blob
whenstopRecording
is called or if the component unmounts
NoteEditorModal
Component
Next, create a new file NoteEditorModal.vue
in the app/components
folder and add the following code to it:
<!-- app/components/NoteEditorModal.vue -->
<template>
<UModal
fullscreen
:close="{
disabled: isSaving || noteRecorder?.isBusy,
}"
:prevent-close="isSaving || noteRecorder?.isBusy"
title="Create Note"
:ui="{
body: 'flex-1 w-full max-w-7xl mx-auto flex flex-col md:flex-row gap-4 sm:gap-6 overflow-hidden',
}"
>
<template #body>
<UCard class="flex-1 flex flex-col" :ui="{ body: 'flex-1' }">
<template #header>
<h3 class="h-8 font-medium text-gray-600 dark:text-gray-300">
Note transcript
</h3>
</template>
<UTextarea
v-model="noteText"
placeholder="Type your note here, or use voice recording..."
size="lg"
:disabled="isSaving || noteRecorder?.isBusy"
:ui="{ root: 'w-full h-full', base: ['h-full resize-none'] }"
/>
</UCard>
<NoteRecorder
ref="recorder"
class="md:h-full md:flex md:flex-col md:w-96 shrink-0 order-first md:order-none"
@transcription="handleTranscription"
/>
</template>
<template #footer>
<UButton
icon="i-lucide-undo-2"
color="neutral"
variant="outline"
:disabled="isSaving"
@click="resetNote"
>
Reset
</UButton>
<UButton
icon="i-lucide-cloud-upload"
:disabled="!noteText.trim() || noteRecorder?.isBusy || isSaving"
:loading="isSaving"
@click="saveNote"
>
Save Note
</UButton>
</template>
</UModal>
</template>
<script setup lang="ts">
import { NoteRecorder } from "#components";
const props = defineProps<{ onNewNote: () => void }>();
type NoteRecorderType = InstanceType<typeof NoteRecorder>;
const noteRecorder = useTemplateRef<NoteRecorderType>("recorder");
const resetNote = () => {
noteText.value = "";
noteRecorder.value?.resetRecordings();
};
const noteText = ref("");
const handleTranscription = (text: string) => {
noteText.value += noteText.value ? "\n\n" : "";
noteText.value += text ?? "";
};
const modal = useModal();
const isSaving = ref(false);
const saveNote = async () => {
const text = noteText.value.trim();
if (!text) return;
isSaving.value = true;
const audioUrls = await noteRecorder.value?.uploadRecordings();
try {
await $fetch("/api/notes", {
method: "POST",
body: { text, audioUrls },
});
useToast().add({
title: "Note Saved",
description: "Your note was saved successfully.",
color: "success",
});
if (props.onNewNote) {
props.onNewNote();
}
modal.close();
} catch (err) {
console.error("Error saving note:", err);
useToast().add({
title: "Save Failed",
description: "Failed to save the note.",
color: "error",
});
}
isSaving.value = false;
};
</script>
The above modal component does the following:
Displays a
textarea
for allowing a manual note entryThe modal integrates the
NoteRecorder
component for voice recordings and manages the data flow between the recordings and thetextarea
for user notes.Whenever a new recording is created, it captures the emitted event from the note recorder component, and appends the transcription text to the
textarea
contentWhen the user clicks the save note button, its first uploads all recordings (if any) by calling the note recorder’s
uploadRecordings
method, and then save the note by calling thenotes
API endpoint created earlier.The save note button first uploads all recordings (if any) asynchronously by calling the
uploadRecordings
method, then sends the note data to the/api/notes
endpoint. Upon success, it notifies the parent by executing the callback passed by it, and then closes the modal.
NoteRecorder
Component
Create a new file NoteRecorder.vue
in the app/components
folder and add the following content to it:
<!-- app/components/NoteRecorder.vue -->
<template>
<UCard
:ui="{
body: 'max-h-36 md:max-h-none md:flex-1 overflow-y-auto',
}"
>
<template #header>
<h3 class="font-medium text-gray-600 dark:text-gray-300">Recordings</h3>
<div class="flex items-center gap-x-2">
<template v-if="state.isRecording">
<div class="w-2 h-2 rounded-full bg-red-500 animate-pulse" />
<span class="mr-2 text-sm">
{{ formatDuration(state.recordingDuration) }}
</span>
</template>
<UButton
:icon="state.isRecording ? 'i-lucide-circle-stop' : 'i-lucide-mic'"
:color="state.isRecording ? 'error' : 'primary'"
:loading="isTranscribing"
@click="toggleRecording"
/>
</div>
</template>
<AudioVisualizer
v-if="state.isRecording"
class="w-full h-14 p-2 bg-gray-50 dark:bg-gray-800 rounded-lg mb-2"
:audio-data="state.audioData"
:data-update-trigger="state.updateTrigger"
/>
<div
v-else-if="isTranscribing"
class="flex items-center justify-center h-14 gap-x-3 p-2 bg-gray-50 dark:bg-gray-800 rounded-lg mb-2 text-gray-500 dark:text-gray-400"
>
<UIcon name="i-lucide-refresh-cw" size="size-6" class="animate-spin" />
Transcribing...
</div>
<div class="space-y-2">
<div
v-for="recording in recordings"
:key="recording.id"
class="flex items-center gap-x-3 p-2 bg-gray-50 dark:bg-gray-800 rounded-lg"
>
<audio :src="recording.url" controls class="w-full h-10" />
<UButton
icon="i-lucide-trash-2"
color="error"
variant="ghost"
size="sm"
@click="removeRecording(recording)"
/>
</div>
</div>
<div
v-if="!recordings.length && !state.isRecording && !isTranscribing"
class="h-full flex flex-col items-center justify-center text-gray-500 dark:text-gray-400"
>
<p>No recordings...!</p>
<p class="text-sm mt-1">Tap the mic icon to create one.</p>
</div>
</UCard>
</template>
<script setup lang="ts">
const emit = defineEmits<{ transcription: [text: string] }>();
const { state, startRecording, stopRecording } = useMediaRecorder();
const toggleRecording = () => {
if (state.value.isRecording) {
handleRecordingStop();
} else {
handleRecordingStart();
}
};
const handleRecordingStart = async () => {
try {
await startRecording();
} catch (err) {
console.error("Error accessing microphone:", err);
useToast().add({
title: "Error",
description: "Could not access microphone. Please check permissions.",
color: "error",
});
}
};
const { recordings, addRecording, removeRecording, resetRecordings } =
useRecordings();
const handleRecordingStop = async () => {
let blob: Blob | undefined;
try {
blob = await stopRecording();
} catch (err) {
console.error("Error stopping recording:", err);
useToast().add({
title: "Error",
description: "Failed to record audio. Please try again.",
color: "error",
});
}
if (blob) {
try {
const transcription = await transcribeAudio(blob);
if (transcription) {
emit("transcription", transcription);
addRecording({
url: URL.createObjectURL(blob),
blob,
id: `${Date.now()}`,
});
}
} catch (err) {
console.error("Error transcribing audio:", err);
useToast().add({
title: "Error",
description: "Failed to transcribe audio. Please try again.",
color: "error",
});
}
}
};
const isTranscribing = ref(false);
const transcribeAudio = async (blob: Blob) => {
try {
isTranscribing.value = true;
const formData = new FormData();
formData.append("audio", blob);
return await $fetch("/api/transcribe", {
method: "POST",
body: formData,
});
} finally {
isTranscribing.value = false;
}
};
const uploadRecordings = async () => {
if (!recordings.value.length) return;
const formData = new FormData();
recordings.value.forEach((recording) => {
if (recording.blob) {
formData.append(
"files",
recording.blob,
`${recording.id}.${recording.blob.type.split("/")[1]}`,
);
}
});
try {
const result = await $fetch("/api/upload", {
method: "PUT",
body: formData,
});
return result.map((obj) => obj.pathname);
} catch (error) {
console.error("Failed to upload audio recordings", error);
}
};
const isBusy = computed(() => state.value.isRecording || isTranscribing.value);
defineExpose({ uploadRecordings, resetRecordings, isBusy });
const formatDuration = (seconds: number) => {
const mins = Math.floor(seconds / 60);
const secs = seconds % 60;
return `${mins}:${secs.toString().padStart(2, "0")}`;
};
</script>
This component does the following:
Allows recording the user’s voice with the help of
useMediaRecorder
composable created earlier. It also integrates theAudioVisualizer
component to enhance the user experience by providing real-time audio feedback during recordings.On a new recording, sends the recorded blob for transcription to the
transcribe
API endpoint, and emits the transcription text on successDisplays all recordings as
audio
elements for users perusal (usingURL.createObjectURL(blob)
). It utilizes theuseRecordings
composable to manage the recordingsUploads the final recordings to R2 (the local disk in dev mode) using the
/api/upload
endpoint, and returns the pathnames of these recordings to the caller (theNoteEditorModal
component)
AudioVisualizer
Component
This component uses an HTML canvas element to represent the audio waveform along a horizontal line. The canvas element is used for its flexibility and efficiency in rendering real-time visualizations, making it suitable for audio waveforms.
The visualization dynamically adjusts based on the amplitude of the captured audio, providing a real-time feedback loop for the user during recording. To do that, it watches the updateTrigger
state variable exposed by useMediaRecorder
to redraw the canvas on audio data changes.
Create a new file AudioVisualizer.vue
in the app/components
folder and add the following code to it:
<!-- app/components/AudioVisualizer.vue -->
<template>
<canvas ref="canvas" width="640" height="100" />
</template>
<script setup lang="ts">
const props = defineProps<{
audioData: Uint8Array | null;
dataUpdateTrigger: number;
}>();
let width = 0;
let height = 0;
const audioCanvas = useTemplateRef<HTMLCanvasElement>("canvas");
const canvasCtx = ref<CanvasRenderingContext2D | null>(null);
onMounted(() => {
if (audioCanvas.value) {
canvasCtx.value = audioCanvas.value.getContext("2d");
width = audioCanvas.value.width;
height = audioCanvas.value.height;
}
});
const drawCanvas = () => {
if (!canvasCtx.value || !props.audioData) {
return;
}
const data = props.audioData;
const ctx = canvasCtx.value;
const sliceWidth = width / data.length;
ctx.clearRect(0, 0, width, height);
ctx.lineWidth = 2;
ctx.strokeStyle = "rgb(221, 72, 49)";
ctx.beginPath();
let x = 0;
for (let i = 0; i < data.length; i++) {
const v = (data[i] ?? 0) / 128.0;
const y = (v * height) / 2;
if (i === 0) {
ctx.moveTo(x, y);
} else {
ctx.lineTo(x, y);
}
x += sliceWidth;
}
ctx.lineTo(width, height / 2);
ctx.stroke();
};
watch(
() => props.dataUpdateTrigger,
() => {
drawCanvas();
},
{ immediate: true },
);
</script>
useRecordings
Composable
The NoteRecorder
component uses the useRecordings
composable to manage the list of recordings, and to clear any used resources. Create a new file useRecordings.ts
in the app/composables
folder and add the following code to it:
// app/composables/useRecordings.ts
export const useRecordings = () => {
const recordings = ref<Recording[]>([]);
const cleanupResource = (recording: Recording) => {
if (recording.blob) {
URL.revokeObjectURL(recording.url);
}
};
const cleanupResources = () => {
recordings.value.forEach((recording) => {
cleanupResource(recording);
});
};
const addRecording = (recording: Recording) => {
recordings.value.unshift(recording);
};
const removeRecording = (recording: Recording) => {
recordings.value = recordings.value.filter((r) => r.id !== recording.id);
cleanupResource(recording);
};
const resetRecordings = () => {
cleanupResources();
recordings.value = [];
};
onUnmounted(cleanupResources);
return {
recordings,
addRecording,
removeRecording,
resetRecordings,
};
};
You can define the Recording
type definition in the shared/types/index.ts
file. This allows for auto import of type definitions in both client & server sides (The intended purpose of the shared folder is for sharing common types & utils between the app & server). Also, while you’re at it, you can also define the Note
type.
// shared/types/index.ts
import type { z } from "zod";
import type { noteSelectSchema } from "#shared/schemas/note.schema";
export type Recording = {
url: string;
blob?: Blob;
id: string;
};
export type Note = z.output<typeof noteSelectSchema>;
Creating the Home Page
Now that we have all the pieces ready for the basic app, it is time to put everything together in a page. Delete the content of the home page (app/pages/index.vue
), and put the following content to it:
<!-- app/pages/index.vue -->
<template>
<UContainer class="h-screen flex justify-center items-center">
<UCard
class="w-full max-h-full overflow-hidden max-w-4xl mx-auto"
:ui="{ body: 'h-[calc(100vh-4rem)] overflow-y-auto' }"
>
<template #header>
<span class="font-bold text-xl md:text-2xl">Voice Notes</span>
<UButton icon="i-lucide-plus" @click="showNoteModal">
New Note
</UButton>
</template>
<div v-if="notes?.length" class="space-y-4">
<NoteCard v-for="note in notes" :key="note.id" :note="note" />
</div>
<div
v-else
class="my-12 text-center text-gray-500 dark:text-gray-400 space-y-2"
>
<h2 class="text-2xl md:text-3xl">No notes created</h2>
<p>Get started by creating your first note</p>
</div>
</UCard>
</UContainer>
</template>
<script setup lang="ts">
import { LazyNoteEditorModal } from "#components";
const { data: notes, refresh } = await useFetch("/api/notes");
const modal = useModal();
const showNoteModal = () => {
modal.open(LazyNoteEditorModal, {
onNewNote: refresh,
});
};
watch(modal.isOpen, (newState) => {
if (!newState) {
modal.reset();
}
});
</script>
On this page we’re doing the following:
Fetch the list of existing notes from the database and display them using the
NoteCard
componentShows a new note button which when clicked opens the
NoteEditorModal
. On successful note creation therefresh
function is called to refetch the notesThe modal state is reset on closure to ensure a clean slate for the next note creation
The cards and modals headers/footers used in the app follow a global style that is defined in the app config file. Centralizing styles in the app configuration ensures consistent theming and reduces redundancy across components.
Create a new file app.config.ts
inside the app
folder, and add the following to it:
// app/app.config.ts
export default defineAppConfig({
ui: {
card: {
slots: {
header: "flex items-center justify-between gap-3 flex-wrap",
},
},
modal: {
slots: {
footer: "justify-end gap-x-3",
},
},
},
});
You’ll also need to wrap your NuxtPage
component with the UApp
component for the modals and toast notifications to work as shown below:
<!-- app/app.vue -->
<template>
<NuxtRouteAnnouncer />
<NuxtLoadingIndicator />
<UApp>
<NuxtPage />
</UApp>
</template>
NoteCard
component
This component displays the note text and the attached audio recordings of a note. The note text is clamped to 3 lines with a show more/less button to show/hide rest of the text. Text clamping ensures that the UI remains clean and uncluttered, while the show more/less button gives users full control over note visibility.
Create a new file NoteCard.vue
in the app/components
folder, and add the following code to it:
<template>
<UCard class="hover:shadow-lg transition-shadow">
<div class="flex-1">
<p
ref="text"
:class="['whitespace-pre-wrap', !showFullText && 'line-clamp-3']"
>
{{ note.text }}
</p>
<UButton
v-if="shouldShowExpandBtn"
variant="link"
:padded="false"
@click="showFullText = !showFullText"
>
{{ showFullText ? "Show less" : "Show more" }}
</UButton>
</div>
<div
v-if="note.audioUrls && note.audioUrls.length > 0"
class="mt-4 flex gap-x-2 overflow-x-auto"
>
<audio
v-for="url in note.audioUrls"
:key="url"
:src="url"
controls
class="w-60 shrink-0 h-10"
/>
</div>
<p
class="flex items-center text-sm text-gray-500 dark:text-gray-400 gap-x-2 mt-6"
>
<UIcon name="i-lucide-clock" size="size-4" />
<span>
{{
note.updatedAt && note.updatedAt !== note.createdAt
? `Updated ${updated}`
: `Created ${created}`
}}
</span>
</p>
</UCard>
</template>
<script setup lang="ts">
import { useTimeAgo } from "@vueuse/core";
const props = defineProps<{ note: Note }>();
const createdAt = computed(() => props.note.createdAt + "Z");
const updatedAt = computed(() => props.note.updatedAt + "Z");
const created = useTimeAgo(createdAt);
const updated = useTimeAgo(updatedAt);
const showFullText = ref(false);
const shouldShowExpandBtn = ref(false);
const noteText = useTemplateRef<HTMLParagraphElement>("text");
const checkTextExpansion = () => {
nextTick(() => {
if (noteText.value) {
shouldShowExpandBtn.value =
noteText.value.scrollHeight > noteText.value.clientHeight;
}
});
};
onMounted(checkTextExpansion);
watch(() => props.note.text, checkTextExpansion);
</script>
And we are done here. Try running the application and create some notes. You should be able to create notes, add multiple recordings to the same note etc. Everything should be working now, or is it?
Try playing the audio recordings of the saved notes, are these playable?
Serving the Audio Recordings
We can’t play the audio recordings because these are saved in R2 (local disk in dev mode), and nowhere we are serving these files. It is time to fix that.
If you look at the /api/notes
code, we save the audio urls/pathnames with an audio
prefix
await useDrizzle()
.insert(tables.notes)
.values({
text,
audioUrls: audioUrls ? audioUrls.map((url) => `/audio/${url}`) : null,
});
The reason to do so was to serve all audio recordings through an /audio
path. Create a new file […pathname].get.ts
in the server/routes/audio
folder and add the following to it:
export default defineEventHandler(async (event) => {
const { pathname } = getRouterParams(event);
return hubBlob().serve(event, pathname);
});
What we’ve done above is to catch all requests to the /audio
path (by using the wildcard […pathname]
in the filename), and serve the requested recording from the storage using hubBlob
.
With this, the frontend is complete, and all functionalities should now work seamlessly.
Further Enhancements
What you’ve created here is a basic version of the application—with all must-have features—that you saw in the beginning of the article. You can further refine the app and take it closer to the demo by:
What you’ve created here is a solid foundation for the application, complete with the core features introduced earlier. To further enhance the app and bring it closer to the full demo version, consider implementing the following features:
Adding a settings page to save post processing settings
Handle post processing in the
/transcribe
api routeAllowing edit/delete of saved notes
Experimenting with additional features that fit your use case or user needs.
If you get stuck while implementing these features, do not hesitate to look at the application source code. The complete source code of the final application is shared at the end of the article.
Deploying the Application
You can deploy the application using either the NuxtHub admin dashboard or through the NuxtHub CLI.
Deploy via NuxtHub Admin
Push your code to a GitHub repository.
Link the repository with NuxtHub.
Deploy from the Admin console.
Learn more about NuxtHub Git integration
Deploy via NuxtHub CLI
npx nuxthub deploy
Learn more about CLI deployment
Source Code
You can find the source code of Vhisper
application on GitHub. The source code includes all the features discussed in this article, along with additional configurations and optimizations shown in the demo.
Conclusion
Congratulations! You've built a powerful application that records and transcribes audio, stores recordings, and manages notes with an intuitive interface. Along the way you’ve touched upon various aspects of Nuxt, NuxtHub and Cloudflare services. As you continue to refine and expand Vhisper, consider exploring additional features and optimizations to further enhance its functionality and user experience. Keep experimenting and innovating, and let this project be a stepping stone to even more ambitious endeavors.
Thank you for sticking with me until the end! I hope you’ve picked up some new concepts along the way. I’d love to hear what you learned or any thoughts you have in the comments section. Your feedback is not only valuable to me, but to the entire developer community exploring this exciting field.
Until next time!
Keep adding the bits and soon you'll have a lot of bytes to share with the world.