Files
svelte-headlessui/src/lib/components/menu/MenuButton.svelte
2021-12-13 18:22:16 -08:00

82 lines
2.3 KiB
Svelte

<script lang="ts">
import { useMenuContext, MenuStates } from "./Menu.svelte";
import { useId } from "$lib/hooks/use-id";
import { Keys } from "$lib/utils/keyboard";
import { Focus } from "$lib/utils/calculate-active-index";
import { tick } from "svelte";
export let disabled = false;
const api = useMenuContext("MenuButton");
const id = `headlessui-menu-button-${useId()}`;
$: buttonStore = $api?.buttonStore;
$: itemsStore = $api?.itemsStore;
async function handleKeyDown(event: KeyboardEvent) {
switch (event.key) {
// Ref: https://www.w3.org/TR/wai-aria-practices-1.2/#keyboard-interaction-13
case Keys.Space:
case Keys.Enter:
case Keys.ArrowDown:
event.preventDefault();
event.stopPropagation();
$api.openMenu();
await tick();
$itemsStore?.focus({ preventScroll: true });
$api.goToItem(Focus.First);
break;
case Keys.ArrowUp:
event.preventDefault();
event.stopPropagation();
$api.openMenu();
await tick();
$itemsStore?.focus({ preventScroll: true });
$api.goToItem(Focus.Last);
break;
}
}
function handleKeyUp(event: KeyboardEvent) {
switch (event.key) {
case Keys.Space:
// Required for firefox, event.preventDefault() in handleKeyDown for
// the Space key doesn't cancel the handleKeyUp, which in turn
// triggers a *click*.
event.preventDefault();
break;
}
}
async function handleClick(event: MouseEvent) {
if (disabled) return;
if ($api.menuState === MenuStates.Open) {
$api.closeMenu();
await tick();
$buttonStore?.focus({ preventScroll: true });
} else {
event.preventDefault();
event.stopPropagation();
$api.openMenu();
await tick();
$itemsStore?.focus({ preventScroll: true });
}
}
$: propsWeControl = {
id,
"aria-haspopup": true,
"aria-controls": $itemsStore?.id,
"aria-expanded": disabled ? undefined : $api.menuState === MenuStates.Open,
};
</script>
<button
{...{ ...$$restProps, ...propsWeControl }}
bind:this={$buttonStore}
on:click={handleClick}
on:keydown={handleKeyDown}
on:keyup={handleKeyUp}
>
<slot open={$api?.menuState === MenuStates.Open} />
</button>