Svelte

The @arraypress waveform family ships three Svelte 5 wrappers, each a thin, typed component over its vanilla core — built with runes ($props, $effect, $derived):

Package	Component(s)	Wraps
@arraypress/waveform-player-svelte	<WaveformPlayer>	@arraypress/waveform-player
@arraypress/waveform-bar-svelte	<WaveformBar>, <WaveformBarTrigger>	@arraypress/waveform-bar
@arraypress/waveform-playlist-svelte	<WaveformPlaylist>	@arraypress/waveform-playlist

Every wrapper follows the same design:

• Prop types are derived from the core’s WaveformPlayerOptions, not re-declared — so they never drift as the core evolves. (The bar is the exception: its core ships no .d.ts, so waveform-bar-svelte hand-declares WaveformBarConfig.)
• The core JS is dynamically import()ed inside $effect, which only runs in the browser — so the audio + canvas + fetch surface never runs during SSR / SvelteKit prerendering.
• The imperative API is exposed as Svelte 5 export functions, reached through bind:this — loadTrack, seekTo, playlist navigation, and the rest.
• CSS is never auto-loaded — you import each core’s stylesheet once at your app entry (e.g. the SvelteKit root +layout.svelte).

Use waveformStyle, not style

On all three components, style is the standard element attribute applied to the host <div> (a CSS string — e.g. for reserving layout height). The core’s style alias for the visual waveform style is not used by the wrappers. To pick a visual style use waveformStyle ('bars' | 'mirror' | 'line' | 'blocks' | 'dots' | 'seekbar'). Likewise class, id, and any other element attribute fall through to the host — the base class is always applied.

---

Player — <WaveformPlayer>

Install

svelte (^5.0.0) and @arraypress/waveform-player (^1.8.0) are peer dependencies — you bring them so you control the versions.

npm

npm install @arraypress/waveform-player-svelte @arraypress/waveform-player svelte

pnpm

pnpm add @arraypress/waveform-player-svelte @arraypress/waveform-player svelte

yarn

yarn add @arraypress/waveform-player-svelte @arraypress/waveform-player svelte

bun

bun add @arraypress/waveform-player-svelte @arraypress/waveform-player svelte

Import the core stylesheet once at your app entry. The wrapper does not import it for you — your bundler should own that decision:

src/routes/+layout.svelte

<script>
  // also works in main.ts for a plain Vite app
  import '@arraypress/waveform-player/dist/waveform-player.css';
</script>

<slot />

Quick start

<script lang="ts">
  import { WaveformPlayer } from '@arraypress/waveform-player-svelte';
</script>

<WaveformPlayer
  url="/audio/track.mp3"
  title="My Track"
  waveformStyle="mirror"
  waveformColor={['#fafafa', '#71717a']}
  showBPM
  ontimeupdate={(currentTime, duration) => {
    /* live progress */
  }}
/>

Props

WaveformPlayerProps is Omit<WaveformPlayerOptions, …callbacks>, so every player option is accepted as a typed prop — height, samples, barRadius, colorPreset, accessibleSeek, markers, gradient-array colours, and so on. See Player → Options for the full inherited surface. Absent props are not forwarded, so the core’s own defaults apply.

src is a shorthand alias for url (provide one; url wins if both are set). class, style, id, and any other element attribute fall through to the host <div> via HTMLAttributes<HTMLDivElement> — the base class wfp-host is always applied.

Prop	Type	Notes
url	string	Audio file URL.
src	string	Shorthand alias for url.
class	string	Appended to the always-present base class wfp-host.
style	string	Inline CSS on the host — e.g. min-height to reserve space before draw.
id	string	Forwarded to the host <div>.

Callback props

Every lifecycle event the core exposes is a lowercase callback prop (matching Svelte’s native onclick / oninput convention), each forwarding the live WaveformPlayer instance:

<WaveformPlayer
  url="/audio/track.mp3"
  onload={(i) => console.log('loaded', i)}
  onplay={() => console.log('playing')}
  onpause={() => console.log('paused')}
  ontimeupdate={(currentTime, duration) => console.log(`${currentTime}s / ${duration}s`)}
  onend={() => console.log('finished')}
  onerror={(err) => console.error('audio failed:', err)}
/>

Prop	Signature	Notes
onload	(instance) => void	Fired once after the waveform is drawn.
onplay	(instance) => void	Playback started (both audio modes).
onpause	(instance) => void	Playback paused (both modes).
onend	(instance) => void	Track ended (external mode synthesizes it at progress ≥ 1).
ontimeupdate	(currentTime, duration, instance) => void	Progress tick. Same argument order in both modes.
onerror	(error, instance) => void	Load / decode / audio error.

Callbacks don’t trigger re-mounts

The lowercase callback props are reactive — the wrapper reads the latest handler through a closure on each call. Passing a fresh inline function never tears the player down; only construction-time props (url, audioMode, visualization options, …) cause a re-mount.

Re-mount semantics

A single $effect synchronously reads every construction prop, so when any of them changes the wrapper destroys the instance and constructs a new one rather than diffing options. Same-url re-mounts are cheap because the core caches decoded peaks keyed by URL. Wrap the component in {#key url} to force a clean remount, or use the imperative loadTrack() below to swap tracks without one.

Imperative control via bind:this

The component exports its API as Svelte 5 export functions. Grab the instance with bind:this and call them directly:

<script lang="ts">
  import { WaveformPlayer } from '@arraypress/waveform-player-svelte';
  let player: WaveformPlayer;
</script>

<WaveformPlayer bind:this={player} url="/audio/track.mp3" />
<button onclick={() => player.togglePlay()}>Play / Pause</button>
<button onclick={() => player.seekTo(60)}>Jump to 1:00</button>
<button onclick={() => player.loadTrack('/audio/next.mp3', 'Next Track', 'Artist')}>
  Load next
</button>

Method	Signature	Notes
play	() => Promise<void> | undefined	Returns the native play() promise in self mode; undefined in external mode.
pause	() => void
togglePlay	() => void
seekTo	(seconds: number) => void	Self mode only.
seekToPercent	(percent: number) => void	Fraction 0..1. Self mode only.
setVolume	(volume: number) => void	0..1. Self mode only.
setPlaybackRate	(rate: number) => void	0.5..2. Self mode only.
setPlayingState	(playing: boolean) => void	External mode — push play/pause visual state.
setProgress	(currentTime, duration) => void	External mode — push the progress overlay from your own clock.
loadTrack	(url, title?, artist?, options?) => Promise<void>	Swap track at runtime; auto-plays unless options.autoplay === false.
getInstance	() => WaveformPlayer | null	Escape hatch — the full core API (load, setWaveformData, refreshTheme, container, statics, …).

Calls before the async import resolves are safe no-ops. The typed handle interface is exported as WaveformPlayerExpose for explicit typing.

DOM events

Prefer the callback props for lifecycle. For the raw waveformplayer:* events (e.g. waveformplayer:request-seek in external mode), reach the container through the instance: player.getInstance()?.container.addEventListener(...).

External audio mode

When pairing with @arraypress/waveform-bar (or any audio controller you own), the player can render visualization only and surrender playback. Drive it via setProgress() / setPlayingState():

<WaveformPlayer
  url={track.url}
  audioMode="external"
  waveformStyle="seekbar"
  showInfo={false}
  height={32}
/>

---

Bar — <WaveformBar> + <WaveformBarTrigger>

The bar is a singleton: render <WaveformBar> once in your root layout, then scatter <WaveformBarTrigger> elements anywhere to play or queue tracks.

Install

Peer deps: @arraypress/waveform-bar (^1.3.1), @arraypress/waveform-player (^1.7.2), svelte (^5.0.0).

npm

npm install @arraypress/waveform-bar-svelte @arraypress/waveform-bar @arraypress/waveform-player svelte

pnpm

pnpm add @arraypress/waveform-bar-svelte @arraypress/waveform-bar @arraypress/waveform-player svelte

yarn

yarn add @arraypress/waveform-bar-svelte @arraypress/waveform-bar @arraypress/waveform-player svelte

bun

bun add @arraypress/waveform-bar-svelte @arraypress/waveform-bar @arraypress/waveform-player svelte

Load order matters

The bar has a hard runtime dependency on the player global. Import the player before the bar at your app entry, or window.WaveformBar will be undefined:

src/routes/+layout.svelte

<script>
  import '@arraypress/waveform-player/dist/waveform-player.css';
  import '@arraypress/waveform-bar/dist/waveform-bar.css';
  import '@arraypress/waveform-player'; // sets window.WaveformPlayer (first)
  import '@arraypress/waveform-bar';    // sets window.WaveformBar    (second)
</script>

<slot />

Mount the bar

Render exactly once in your root layout. On mount the component renders a persist host, dynamically imports the core, and calls window.WaveformBar.init(config); on unmount it calls destroy() so route changes don’t leak listeners.

src/routes/+layout.svelte

<script lang="ts">
  import { WaveformBar } from '@arraypress/waveform-bar-svelte';
</script>

<slot />

<WaveformBar
  config={{
    persist: true,
    continuous: true,
    showQueue: true,
    actions: {
      favorite: { endpoint: '/api/favorites' },
      cart: { endpoint: '/api/cart' },
    },
  }}
/>

<WaveformBar> prop	Type	Default	Notes
config	WaveformBarConfig	undefined	Passed verbatim to init(). See table below.
persist	boolean	true	Relocate the .waveform-bar element under the host <div> so it survives route changes.
hostId	string	'waveform-bar-host'	DOM id of the persist host.

class and any other attribute fall through to the host <div> (base class wb-host).

Config change detection

init() re-runs only when the config’s structural shape changes — compared via a $derived JSON.stringify key. Passing a fresh object with the same shape on every render is safe. Function endpoints (actions.*.endpoint) collapse to a sentinel in that key, so pass stable references for those to avoid re-init churn.

WaveformBarConfig

waveform-bar-svelte hand-declares this type (the bar core ships no .d.ts), so this is the source of truth for the typed config surface. Every field is optional.

Group	Fields
Behaviour	persist, autoResume, continuous, repeat ('off' | 'all' | 'one')
UI toggles	showQueue, showPrevNext, showRepeat, showVolume, showMute, showTime, showTrackLink, showMeta, maxMeta (number)
Layout	wide, position ('bottom' | 'top'), collapsible, mode ('waveform' | 'classic'), showShuffle, shuffle
Theming	defaultArtwork (string | null), theme ('dark' | 'light' | null)
Waveform	waveform (boolean), waveformStyle, waveformHeight, barWidth, barSpacing, waveformColor, progressColor, markerColor
Sharing / errors	share, shareParam, errorText
Volume / storage	volume, storageKey
Server actions	actions ({ favorite?, cart? }, each { endpoint, method?, headers? })

mode picks the layout

mode defaults to 'waveform' (the standard layout with a width-adjustable waveform canvas — pair it with wide to span the viewport). Set mode: 'classic' for a Spotify-style centre layout with a full-width seek bar instead of the waveform. There is no maxWidth field — width is controlled by wide and mode.

Trigger a track

<WaveformBarTrigger> emits the data-wb-* attribute contract the bar scans for; the core library handles click delegation. It is polymorphic via as — a <button> by default — and forwards every standard DOM attribute (onclick, data-testid, role, …) to the rendered element via ...rest.

<script lang="ts">
  import { WaveformBarTrigger } from '@arraypress/waveform-bar-svelte';
  export let track;
</script>

<article>
  <h3>{track.title}</h3>

  <!-- Default: a <button> with auto play/pause icons -->
  <WaveformBarTrigger
    url={track.url}
    id={track.id}
    title={track.title}
    artist={track.artist}
    artwork={track.cover}
  />

  <!-- Append to the queue with custom content -->
  <WaveformBarTrigger mode="queue" url={track.url} title={track.title}>
    + Queue
  </WaveformBarTrigger>

  <!-- Wrap a whole card as the trigger -->
  <WaveformBarTrigger as="div" url={track.url} title={track.title} noDefaultIcons>
    <div class="card-body"><!-- … --></div>
  </WaveformBarTrigger>
</article>

Track data props (WaveformBarTrackData) — each maps 1:1 to a data-wb-* attribute; arrays are JSON-encoded, and absent props emit no attribute:

Prop	Type	Notes
url	string	Play target + identity.
id	string	Defaults to url.
title, artist, album, artwork, link	string	Display metadata.
duration, bpm	string | number
musicalKey	string	→ data-wb-key.
meta	string[]	Extra metadata chips.
waveform	number[] | string	Pre-computed peaks or .json URL.
markers	WaveformBarMarker[]	DJ-mode cue markers ({ time, label, title?, artist?, artwork?, bpm?, key?, color? }).
favorited, inCart	boolean	Initial action state.

Trigger-specific props:

Prop	Type	Default	Notes
mode	'play' | 'queue'	'play'	Immediate play vs. append to queue.
as	'button' | 'a' | 'div' | 'span'	'button'	Rendered tag.
href	string	—	Used when as="a".
noDefaultIcons	boolean	false	Suppress the injected play/pause SVGs.
aria-label	string	auto	Auto-generated from title when absent.
class	string	—	Appended to the base class wb-icon-swap.

Slotted children replace the default icons. class, native listeners (onclick), and any other DOM attribute fall through to the rendered element.

No callback props on the bar

The bar deliberately exposes no callback props (and no imperative handle) — an inline function each render would needlessly re-init the singleton. The core dispatches every state change as a bubbling waveformbar:* CustomEvent (e.g. waveformbar:play, waveformbar:trackchange); listen via addEventListener in your own effect. That stays framework-agnostic and avoids re-init churn.

---

Playlist — <WaveformPlaylist>

A declarative tracks array with optional chapters, an embedded player, and imperative track / chapter navigation.

Install

Peer deps: @arraypress/waveform-playlist (^1.3.0), @arraypress/waveform-player (^1.8.0), svelte (^5.0.0).

npm

npm install @arraypress/waveform-playlist-svelte @arraypress/waveform-playlist @arraypress/waveform-player svelte

pnpm

pnpm add @arraypress/waveform-playlist-svelte @arraypress/waveform-playlist @arraypress/waveform-player svelte

yarn

yarn add @arraypress/waveform-playlist-svelte @arraypress/waveform-playlist @arraypress/waveform-player svelte

bun

bun add @arraypress/waveform-playlist-svelte @arraypress/waveform-playlist @arraypress/waveform-player svelte

Import both stylesheets, and import the player core for its global side effect — the playlist constructs new window.WaveformPlayer(...) for the active track:

src/routes/+layout.svelte

<script>
  import '@arraypress/waveform-player'; // registers window.WaveformPlayer
  import '@arraypress/waveform-player/dist/waveform-player.css';
  import '@arraypress/waveform-playlist/dist/waveform-playlist.css';
</script>

<slot />

Quick start

<script lang="ts">
  import { WaveformPlaylist } from '@arraypress/waveform-playlist-svelte';
</script>

<WaveformPlaylist
  continuous
  waveformStyle="bars"
  tracks={[
    { url: '/audio/a.mp3', title: 'Track A', artist: 'Artist' },
    {
      url: '/audio/b.mp3',
      title: 'Track B',
      chapters: [
        { time: 0, label: 'Intro' },
        { time: '1:30', label: 'Verse' },
        { time: 180, label: 'Chorus', color: '#22d3ee' },
      ],
    },
  ]}
/>

Each track renders into the [data-track] / [data-chapter] markup the playlist constructor parses on mount. The host carries the base class wfp-host.

tracks (required)

WaveformPlaylistTrackInput[]:

Field	Type	Notes
url	string	Required → data-url.
title	string	Falls back to the filename if omitted.
artist	string	Artist row.
artwork	string	Artwork URL.
album	string	Media Session metadata.
duration	string	Display duration, e.g. '3:45'.
markers	WaveformPlaylistMarker[]	JSON-encoded into data-markers.
chapters	WaveformPlaylistChapterInput[]	{ time: number | string, label, color? } — time accepts seconds or 'M:SS'.

Props

WaveformPlaylistProps combines three groups:

1. Playlist options picked from WaveformPlaylistOptions: continuous, expandChapters, showDuration, showChapterMarkers, chapterMarkerColor, showPlayState.
2. Pass-through player options — the full WaveformPlayerOptions visualization / colour / behaviour surface, minus per-track content (url, src, title, artist, artwork, album, markers, waveform), the style alias, the player’s own layout, and the lifecycle callbacks.
3. Svelte extras — the required tracks, plus class, style, id and other element attributes (fall through to the host).

Prop	Type	Default	Notes
tracks	WaveformPlaylistTrackInput[]	—	Required. An empty array renders an empty playlist (the core skips init).
layout	'list' | 'minimal'	'list'	Full track list vs. compact button switcher. Overrides the player’s own layout.
class	string	—	Appended to wfp-host.
style	string	—	Inline CSS on the host.
id	string	—	Forwarded to the host <div>.

Common pass-through player props include waveformStyle, height, colorPreset, waveformColor, progressColor, showBPM, accessibleSeek, and autoplay — see Player → Options for the complete list.

The same lowercase lifecycle callback props as the player (onload, onplay, onpause, onend, ontimeupdate, onerror) are accepted and forwarded to the embedded player; like the player’s, they reach the live instance through reactive closures and never trigger a re-mount. For richer control, reach the embedded player directly through getPlayer().

Imperative navigation via bind:this

<script lang="ts">
  import { WaveformPlaylist } from '@arraypress/waveform-playlist-svelte';
  let playlist: WaveformPlaylist;
  export let tracks;
</script>

<WaveformPlaylist bind:this={playlist} {tracks} continuous />
<button onclick={() => playlist.previousTrack()}>Prev</button>
<button onclick={() => playlist.nextTrack()}>Next</button>
<button onclick={() => playlist.selectTrack(0)}>First</button>

Method	Signature	Notes
selectTrack	(index: number) => void	Select + load a track by index.
seekToChapter	(trackIndex, time) => void	Loads the target track first if needed, then seeks.
nextTrack	() => void
previousTrack	() => void
getPlayer	() => unknown | null	The embedded WaveformPlayer instance (full player API).
getCurrentTrackIndex	() => number
getTracks	() => WaveformPlaylistTrack[]	Parsed tracks (with resolved element / index).
getInstance	() => WaveformPlaylist | null	Escape hatch for anything else.

Calls before the async import resolves are safe no-ops. The typed handle interface is exported as WaveformPlaylistExpose.

Re-mount semantics

Changing tracks (compared by serialized value) or any construction-time option tears the playlist down and rebuilds it against the freshly rendered markup. For navigation without a re-mount, use the handle above.

---

Server-side rendering

All three components are SSR / SvelteKit-prerender safe by construction: the host markup (and, for the playlist, the [data-track] children) renders on the server, and the browser-only core is dynamically import()ed inside $effect. Because effects never run during SSR, the audio + canvas surface only evaluates after hydration on the client — no import.meta.env.SSR guard or {#if browser} wrapper is needed.

Reserve layout space with the style attribute (e.g. style="min-height: 96px") to avoid a content shift before the waveform draws, and import each core’s CSS once in your root +layout.svelte (for the bar, remember the player-before-bar load order above).

Related

Player options

Full inherited option surface — Player → Options.

Events

The waveformplayer:* DOM events — Player → Events.

React

The same wrappers, typed for React — React.

Installation

Bundler, CDN, and CSS setup — Getting started.