`Metric`¶

Display a labelled value and optional directional change.


Import	`from hedron import Metric`
Distribution	`hedron`
Backend activity	No
Normal render mode	`RenderMode.FRAGMENT`

Live demo¶

Monthly revenue: $84,200; ↗ +8.4%

The preview is a local docs simulation (not a running Hedron server). Interactive demos show a “Simulated HTMX” trace when applicable.

Basic use¶

from hedron import Metric
component = Metric('Monthly revenue', '$84,200', delta='+8.4%', delta_tone='up')

Compose under Page for full documents, or return from a fragment route for HTMX swaps.

How it works¶

Metric uses a description list so label, value, and delta remain related in non-visual reading. Tone is exposed as data for theming.

This component's core behavior is server-rendered HTML and does not require a browser runtime. The preview is ordinary semantic HTML, so keyboard, form, link, and disclosure behavior comes from the platform.

Constructor and parameters¶

Metric(label, value, *, delta=None, delta_tone='neutral')

Parameter	Type	Meaning
`label`	`str`	Metric name.
`value`	`object`	Current value converted to text.
`delta`	`object \| None`	Optional change.
`delta_tone`	`up \| down \| neutral`	Domain-aware direction token.

Composition and backend behavior¶

Keep Metric at the smallest semantic boundary. Fragment routes should return only the replaced region and preserve stable target IDs across success, validation, empty, loading, and error responses.

Metric is primarily presentational; keep any mutation on an explicit action or component route.

Accessibility¶

Include a time window, unit, and whether up/down is good when context does not make that obvious.

Security¶

Escaping and SafeUrl / TrustedHtml are framework concerns; authorization and data exposure remain application code. Redact secrets before rendering.

Common mistakes¶

Never rely on green/red or arrows alone to explain the delta.
Do not copy docs-preview JavaScript into an application server.

Testing¶

from hedron import RenderMode, render

result = render(component, mode=RenderMode.FRAGMENT)
assert result.html
assert not result.diagnostics

All component demos · Built-in API · Testing

Metric¶