`Select`¶

Choose one value from server-defined label/value options.


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

Live demo¶

Region

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 Select
component = Select('region', [('iad', 'US East'), ('fra', 'Europe')], value='iad')

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

How it works¶

Options are explicit value/label pairs and the selected value is matched server-side during rendering. The result is a native single-select.

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¶

Select(name, options, *, id=None, required=False, value=None, depends_on=None, source=None)

Parameter	Type	Meaning
`name`	`str`	Submitted field name.
`options`	`Sequence[tuple[str, str]]`	Value/label pairs.
`id`	`str \| None`	Control ID.
`required`	`bool`	Native required constraint.
`value`	`str \| None`	Selected option value.
`depends_on`	`str \| None`	Parent field name; compiles `hx-trigger="change from:#field-{dom_id_part(name)}"`.
`source`	`str \| None`	Child `hx-get` fragment that synthesizes options.

Composition and backend behavior¶

Keep Select 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.

Select participates in interaction markup. Pair it with an explicit @app.action POST (and CSRF) when the control mutates state.

Accessibility¶

Use meaningful option labels and include a non-value prompt option when no default is appropriate.

Security¶

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

Common mistakes¶

Validate the submitted value against the authoritative server-side option set.
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

Select¶