SelectItem
SelectItem is the compact option record used by Select.
It is not a widget on its own. Instead, it carries the label, optional icon, and already-prepared action for one row in the opened select menu.
Select adapts it to the shared MenuActionItem::option anatomy, so option
rows use the same retained menu recipe as other command and list-box surfaces.
Example
use fission::prelude::*;
let items = vec![
SelectItem {
label: "Compact".into(),
icon: None,
on_select: ActionEnvelope {
id: set_density_id,
payload: serde_json::to_vec(&SetDensity(Density::Compact)).unwrap(),
},
semantics_identifier: Some("density.compact".into()),
},
SelectItem {
label: "Comfortable".into(),
icon: None,
on_select: ActionEnvelope {
id: set_density_id,
payload: serde_json::to_vec(&SetDensity(Density::Comfortable)).unwrap(),
},
semantics_identifier: Some("density.comfortable".into()),
},
];
Each item contains the final action for that option, so Select does not have to guess how your state model works.
Field table
Field | Type | Meaning | Notes / default behavior |
|---|---|---|---|
label | String | Visible text for the option row. | Required. |
icon | Option<String> | Optional icon source shown before the label. | Defaults to None. |
on_select | ActionEnvelope | Action dispatched when this option is chosen. | Required. Usually updates the selected value and closes the menu. |
semantics_identifier | Option<String> | Stable identifier exposed on the generated option semantic node. | Use it when visible labels may be duplicated or localized. |
How to think about it
Because SelectItem stores a ready-made ActionEnvelope, it works best when every item can prepare its own payload during build. That is exactly what you want for enums, ids, and other small typed choices.
A good reducer usually stores the real selected value in state and derives selected_label separately. Do not let the label string become your only source of truth unless the label is the product value.
The parent renders each record as a semantic Option. The first item whose
label exactly equals Select::selected_label is marked selected and receives
the selected visual treatment. Its stable id also becomes the open trigger's
active descendant and the flyout's selected-row alignment target. When items
can be reordered or translated, give each one a stable
semantics_identifier; otherwise its retained popup identity is derived from
its current index.
Specific advice
Make the on_select action do both pieces of work the user expects: set the new value and close the select by updating is_open in state. The widget itself will not close unless your state says so.
SelectItem has no disabled or description fields. When those states are part
of the product model, use the lower-level MenuContent::list_box and
MenuActionItem anatomy in a deliberately owned composite rather than making
an option look unavailable while leaving it actionable.
Production checklist
For SelectItem, review the fields that change behavior before treating the widget as finished: label, icon, on_select, and semantics_identifier. The goal is to make the product rule visible in state and actions, not hidden inside ad-hoc construction code.
•
Bind on_select to explicit reducer actions and test that the reducer handles unavailable, duplicate, or invalid input safely.
•
Check the semantics tree for the user-facing label or role that makes this widget understandable without relying only on pixels.
•
Add at least one component or harness test that confirms the visible text, semantic role, action dispatch, and layout constraint that matter for this widget in context.
If a screen starts repeating the same SelectItem setup, extract a named component around this widget. That keeps the reference API small while making product code easier to read and safer for generated code to copy.