Configuration

`init(config)` options

WaveformBar.init(config = {}) builds the bar, the queue panel, and the embedded player; binds triggers; observes the DOM and theme; restores persisted volume/favorites/queue state; and applies any share-link target from the URL. Every option is optional.

Playback & queue

Option	Type	Default	Description
`continuous`	`boolean`	`true`	Auto-advance to the next queue track when a track ends (and on track error).
`autoResume`	`boolean`	`true`	On restore, resume playback if the saved state was playing. Falls back to paused if the browser blocks autoplay.
`repeat`	`'off' \| 'all' \| 'one'`	`'off'`	Initial repeat mode. `'all'` loops the queue; `'one'` loops the current track.
`volume`	`number`	`1`	Initial volume `0..1` (clamped; `NaN`/out-of-range coerced to `1`). Overridden by persisted volume when `persist` is on.
`persist`	`boolean`	`true`	Save queue/index/position/playing to `sessionStorage`, and volume/mute/favorites to `localStorage`. Also gates the collapsed-state save.
`storageKey`	`string`	`'waveform-bar'`	Storage key prefix. See Persistence.

Controls visibility

Buttons render only when their flag (or the relevant config) is set. The methods behind them still work programmatically even when the button is hidden.

Option	Type	Default	Description
`showRepeat`	`boolean`	`true`	Render the repeat-cycle button.
`showQueue`	`boolean`	`true`	Render the queue toggle button and create the queue panel. `false` = no panel at all.
`showPrevNext`	`boolean`	`true`	Render the prev/next skip buttons.
`showVolume`	`boolean`	`true`	Render the volume popup slider.
`showMute`	`boolean`	`true`	Render the mute/volume button. The volume wrapper renders if `showMute` or `showVolume` is true.
`showMeta`	`boolean`	`true`	Render the metadata tag strip (BPM/key/duration/custom).
`showTrackLink`	`boolean`	`true`	Make the track-info area clickable, navigating to the track’s `data-link` (scheme-guarded).
`maxMeta`	`number`	`3`	Maximum number of metadata tags shown in the bar.
`collapsible`	`boolean`	`false`	Render a collapse button that shrinks the bar to a floating transport pill.
`share`	`boolean`	`false`	Render a “copy share link” button (emits a URL with the timestamp + track identity).

Layout & theme

Option	Type	Default	Description
`position`	`'bottom' \| 'top'`	`'bottom'`	Which edge the bar docks to. `'top'` adds `.wb-top` and flips the slide direction.
`theme`	`'dark' \| 'light' \| null`	`null`	Force a theme. `null` = auto-detect from the page and re-detect live (see Theming).
`mode`	`'waveform' \| 'classic'`	`'waveform'`	`'classic'` is a Spotify-style centre layout: now-playing left, transport centred over a full-width seek bar, controls right.
`wide`	`boolean`	`false`	Waveform mode only. `true` sets `--wb-max-width: 100%`, lifting the 1400px content cap.
`showShuffle`	`boolean`	`false`	Show a shuffle toggle in the transport cluster.
`shuffle`	`boolean`	`false`	Start with shuffle (random queue advance) on.
`defaultArtwork`	`string \| null`	`null`	Fallback artwork URL when a track has no `artwork`.

Embedded player (waveform)

These pass through to the bar’s single embedded WaveformPlayer instance.

Option	Type	Default	Description
`waveform`	`boolean`	`true`	`false` forces the player’s built-in `seekbar` style (classic Spotify-style progress bar instead of a waveform).
`waveformStyle`	`string`	`'mirror'`	Player style: `'bars'`, `'mirror'`, `'line'`, `'blocks'`, `'dots'`, `'seekbar'`. Ignored when `waveform: false`.
`waveformHeight`	`number`	`32`	Waveform height in px (passed to the player as `height`).
`barWidth`	`number`	`2`	Waveform bar width in px.
`barSpacing`	`number`	`2`	Gap between waveform bars in px.
`waveformColor`	`string \| null`	`null`	Waveform color. Only passed to the player when truthy (else the player auto-detects from the theme).
`progressColor`	`string \| null`	`null`	Progress color. Only passed when truthy.
`markerColor`	`string`	`'rgba(255, 255, 255, 0.25)'`	Default marker line color for markers lacking their own `color`.
`errorText`	`string \| null`	`null`	Custom “audio failed to load” message passed to the player. `null` = the player’s own default.
`crossOrigin`	`'anonymous' \| 'use-credentials' \| null`	`null`	CORS mode forwarded to the embedded `<audio>`. Only passed when truthy. `null` leaves it unset (native `<audio>` behavior — avoids breaking CDN media without CORS headers).

Option	Type	Default	Description
`share`	`boolean`	`false`	Render the copy-share-link button.
`shareParam`	`string`	`'wt'`	URL query param carrying the shared timestamp in seconds (e.g. `?wt=42`).

Server actions

actions wires the heart and cart buttons to your backend. The buttons only render when their action config is present.

actions: {
  favorite?: { endpoint: string | ((payload) => any), method?: string, headers?: object },
  cart?:     { endpoint: string | ((payload) => any), method?: string, headers?: object }
} | null  // default: null

A string endpoint is fetch()’d with a JSON body (method defaults to 'POST', plus any headers).
A function endpoint is called with the payload object directly — use it for client-side carts or custom transports.

WaveformBar.init({
  actions: {
    favorite: { endpoint: '/api/favorites', method: 'POST', headers: { 'X-CSRF': token } },
    cart:     { endpoint: (payload) => myCart.add(payload) }
  }
});

Payloads sent by the bar:

Action	Payload
favorite	`{ action: 'favorite', id, url, title, favorited }`
cart	`{ action: 'cart', id, url, title }`

Callbacks

Config callbacks fire alongside the DOM events but are scoped to your init() call.

Option	Signature	Fires when
`onPlay`	`(track) => void`	Playback starts.
`onPause`	`(track) => void`	Playback pauses.
`onTrackChange`	`(track, index) => void`	The current track changes.
`onQueueChange`	`(queue, currentIndex) => void`	A track is added/removed/cleared. Not fired by `play()`-driven insertions.
`onVolumeChange`	`(volume) => void`	`setVolume` runs (and the unmute path). Not fired by the mute-only branch.
`onFavorite`	`(track, favorited) => void`	`toggleFavorite` runs.
`onCart`	`(track) => void`	`addToCart` runs.