# Sparkline (`sparkline`)
A headline number with its recent shape — the smallest chart: a current value, its bucket label, and an area glyph.
> **Layer:** L1 surface · **Recipe:** _(unset — see docs/agent/pick-a-surface.md)_
> Curriculum: `AGENTS.md` · pick matrix: `docs/agent/pick-a-surface.md` · blast radius: `CONSUMER_MAP.md`
> **Dialect:** Partial below is **unprefixed** (gallery / standalone HM). DOM contract Python often uses the **source token** `data-dz-*` / `dz-*` (Dazzle dual-lock). Match the CSS/JS bundle you load.
> **Demo vs contract:** Live gallery behaviour may use `/mock/*` or flash toasts. Those are **offline demos only** — implement **Server exchange** + **DOM contract**, not the mock. See AGENTS.md › Gallery demos.
## Copy this
```html
184msthis hour
```
## Server exchange
This Hyperpart has **no server exchange** — presentation or client chrome only. If you put `hx-*` on a control that uses this markup, that action's exchange belongs to the action, not this part.
## Swap contract
Agent-visible HTMX topology (ADR-0054 / decision 0012). **Exchange envelope** = what the response may re-emit relative to the persistent slot (`body_only` | `outer` | `none` | `host_owned` | `document`). Dual-lock validates part markup only — not this envelope. Stem: `stems/morph-safe-hypermedia.md`.
**No host HTMX exchange** on this part — presentation or client chrome only. **Exchange envelope:** `n/a`.
If a **host** wraps this markup in `hx-*`, **that host owns the swap contract** (sole identity + envelope). Prefer `innerMorph` / `outerMorph` for stable slots; replacement for flash; body-only responses under inner swaps.
### Envelope response examples
What the **server returns** for each exchange. Match the **exchange envelope**; dual-lock still applies to interior markup.
This part has no owned exchange (envelope `n/a`). If a host adds `hx-*`, that host’s envelope applies — typically `body_only`:
```html
content…
```
Do **not** re-own the slot:
```html
…
```
## How to use it
No extended guidance authored yet — start from Copy this and the dependency chips.
### Seams
- copy the partial under Copy this; keep root class and data-* modifiers so the CSS/JS bundle matches
- no Server exchange on this part — pure presentation or client chrome
- satisfy the DOM contract tables (CI stop-ship)
## DOM contract
What emitted markup must satisfy (CI: `tests/test_contracts.py`). Do not invent attrs outside the tables. Python modules under `contracts/` are **package-internal dual-locks** (`from contracts._kit import …`) — not FastAPI business handlers. App servers implement **Server exchange** endpoints; this section constrains the HTML those endpoints return.
### `contracts/sparkline.py`
- **Required root:** `[data-dz-sparkline]` (part `sparkline`)
| Node | Attr | Constraint |
|---|---|---|
| `[data-dz-sparkline]` | `data-dz-sparkline` | present (any value) |
#### Ingestion model `Sparkline`
| Field | Type | Required |
|---|---|---|
| `points` | `array` | no |
| `empty_message` | `string` | no |
#### Exemplar `render()`
```python
def render(s: Sparkline) -> str:
"""Model → sparkline region (matches Dazzle emitter geometry)."""
if not s.points:
return (
f'
'
f'
{html.escape(s.empty_message)}
'
f"
"
)
last_label, last_value = s.points[-1]
last_value_str = str(int(last_value)) if last_value == int(last_value) else str(last_value)
max_val = max(v for _, v in s.points)
if max_val <= 0:
max_val = 1.0
max_val_str = str(int(max_val)) if max_val == int(max_val) else str(max_val)
count = len(s.points)
headline = (
f'