Module

Halogen.Widgets.Accordion.Internal

Package: purescript-halogen-widgets
Repository: afcondon/purescript-halogen-widgets

Shared core for the two accordion orientations. Not a widget itself — it carries no public component; the orientation-fixed VAccordion and HAccordion modules wrap mkComponent and re-export this surface so each satisfies the uniform-exports rule (CONTRACT.md rule 4).

One accordion is one panel's interactive header. Clicking it emits Toggled carrying the requested new open value; the component never flips its own state. The PARENT owns open and renders the panel BODY itself (if open then [body] else []) — see CONTRACT.md rule 5.

The toggle is debounced inside the component (configurable via Input.debounce) — the machinery Triggerfish hand-rolls as markTap / lastTapMicros to stop a 30 fps re-render double-dispatch from cancelling a panel flip, absorbed once for everyone.

Orientation is the only thing the two wrappers differ on, and it changes only the collapsed rendering:

Vertical — panels stack top-to-bottom. The header is always a full-width horizontal bar; collapsing just hides the parent's body and flips the chevron (▾ → ▸). This is the common web accordion.
Horizontal — panels sit side-by-side as columns (Triggerfish). A collapsed panel shrinks to a thin vertical strip with a rotated label.

#Input Source

type Input = { debounce :: Milliseconds, disabled :: Boolean, label :: String, motion :: Motion, open :: Boolean, sub :: Maybe String }

Controlled input. The parent owns open; everything else is config.

#Output Source

data Output

A request, not a fact: the user asked for this new open value.

Constructors

Toggled Boolean

#Query Source

data Query a

Imperative escape hatch. Rarely needed — Input is the main channel — but present so every widget's Slot has the same shape. SetOpen requests a value just as a click would.

Constructors

SetOpen Boolean a

#Slot Source

type Slot = Slot Query Output

#Orientation Source

data Orientation

Which way the accordion lays out. Fixed per-component by the wrapper.

Constructors

Vertical
Horizontal

#mkComponent Source

mkComponent :: forall m. MonadAff m => Orientation -> Component Query Input Output m

Build an accordion component fixed to one orientation.

#defaultInput Source

defaultInput :: String -> Input

A sensible starting Input; override the fields you care about. The 120 ms default coalesces a double-dispatched click into one Toggled. motion defaults to NoMotion — the header snaps, as it always has; opt into eased chevron rotation by overriding it (and pair with Accordion.body for an eased body reveal).

#body Source

body :: forall w i. { motion :: Motion, open :: Boolean } -> Array (HTML w i) -> HTML w i

Tier-2 chrome (CONTRACT.md rule 5): an OPTIONAL animated wrapper for the panel body the parent renders. The accordion component is only the header; the body has always been the parent's, written if open then [body] else []. That form unmounts the body when collapsed, which is exactly why it cannot animate. body keeps the content mounted and eases its height with the CSS grid-rows 0fr↔1fr trick, so it slides.

The trade-off, made explicit: the body stays in the DOM while collapsed (at height 0). For a presentational body that costs nothing; for a body of live, expensive children, weigh it — the plain if open then … unmount is still the right call when you want the collapsed body genuinely gone, and is lighter when you are not animating at all. Reach for body when you want the reveal eased (pass the same motion you gave the header).

It is action-polymorphic, like Panel/Modal: your body content threads straight through, so it carries your interactive children untouched.

Modules: Halogen.Widgets.Accordion.Internal; Halogen.Widgets.Compare; Halogen.Widgets.DoubleKnob; Halogen.Widgets.Field; Halogen.Widgets.HAccordion; Halogen.Widgets.Knob; Halogen.Widgets.Modal; Halogen.Widgets.Motion; Halogen.Widgets.Panel; Halogen.Widgets.SegmentedControl; Halogen.Widgets.Select; Halogen.Widgets.Slider; Halogen.Widgets.Stepper; Halogen.Widgets.Style; Halogen.Widgets.Toast; Halogen.Widgets.Toggle; Halogen.Widgets.VAccordion