From b5af395c1f50823244a6ee174638cc9e98379200 Mon Sep 17 00:00:00 2001
From: anatolzak <53095479+anatolzak@users.noreply.github.com>
Date: Thu, 18 Apr 2024 13:49:33 +0300
Subject: [PATCH] add escape layer

---
 packages/bits-ui/src/lib/bits/index.ts        |  1 +
 .../escape-layer/escape-layer.svelte          | 15 +++++
 .../escape-layer/escape-layer.svelte.ts       | 57 +++++++++++++++++++
 .../lib/bits/utilities/escape-layer/index.ts  |  3 +
 .../lib/bits/utilities/escape-layer/types.ts  | 27 +++++++++
 5 files changed, 103 insertions(+)
 create mode 100644 packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte
 create mode 100644 packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte.ts
 create mode 100644 packages/bits-ui/src/lib/bits/utilities/escape-layer/index.ts
 create mode 100644 packages/bits-ui/src/lib/bits/utilities/escape-layer/types.ts

diff --git a/packages/bits-ui/src/lib/bits/index.ts b/packages/bits-ui/src/lib/bits/index.ts
index e7d66f381..439fccacd 100644
--- a/packages/bits-ui/src/lib/bits/index.ts
+++ b/packages/bits-ui/src/lib/bits/index.ts
@@ -33,3 +33,4 @@ export * as Toggle from "./toggle/index.js";
 export * as ToggleGroup from "./toggle-group/index.js";
 export * as Toolbar from "./toolbar/index.js";
 export * as Tooltip from "./tooltip/index.js";
+export * as EscapeLayer from "./utilities/escape-layer/index.js";
diff --git a/packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte b/packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte
new file mode 100644
index 000000000..baba6f377
--- /dev/null
+++ b/packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte
@@ -0,0 +1,15 @@
+<script lang="ts">
+	import type { EscapeLayerProps } from "./types.js";
+	import { escapeLayerState } from "./escape-layer.svelte.js";
+	import { readonlyBox } from "$lib/internal/box.svelte.js";
+	import { noop } from "$lib/index.js";
+
+	let { behaviorType = "close", onEscape = noop, children }: EscapeLayerProps = $props();
+
+	escapeLayerState({
+		behaviorType: readonlyBox(() => behaviorType),
+		onEscape: readonlyBox(() => onEscape),
+	});
+</script>
+
+{@render children?.()}
diff --git a/packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte.ts b/packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte.ts
new file mode 100644
index 000000000..fdd30553c
--- /dev/null
+++ b/packages/bits-ui/src/lib/bits/utilities/escape-layer/escape-layer.svelte.ts
@@ -0,0 +1,57 @@
+import { onDestroy } from "svelte";
+import type { EscapeBehaviorType, EscapeLayerProps } from "./types.js";
+import type { ReadonlyBox, ReadonlyBoxedValues } from "$lib/internal/box.svelte.js";
+import { type EventCallback, addEventListener } from "$lib/internal/events.js";
+import { kbd } from "$lib/internal/kbd.js";
+
+const layers = new Map<EscapeLayerState, ReadonlyBox<EscapeBehaviorType>>();
+
+type EscapeLayerStateProps = ReadonlyBoxedValues<Required<Omit<EscapeLayerProps, "children">>>;
+
+export class EscapeLayerState {
+	#onEscapeProp: ReadonlyBox<EventCallback<KeyboardEvent>>;
+	#behaviorType: ReadonlyBox<EscapeBehaviorType>;
+
+	constructor(props: EscapeLayerStateProps) {
+		this.#behaviorType = props.behaviorType;
+		this.#onEscapeProp = props.onEscape;
+		layers.set(this, this.#behaviorType);
+		const unsubEvents = this.#addEventListener();
+		onDestroy(() => {
+			unsubEvents();
+			layers.delete(this);
+		});
+	}
+
+	#addEventListener() {
+		return addEventListener(document, "keydown", this.#onkeydown, { passive: false });
+	}
+
+	#onkeydown = (e: KeyboardEvent) => {
+		if (e.key !== kbd.ESCAPE || !isResponsibleEscapeLayer(this)) return;
+		e.preventDefault();
+		const behaviorType = this.#behaviorType.value;
+		if (behaviorType !== "close" && behaviorType !== "defer-otherwise-close") return;
+		this.#onEscapeProp.value(e);
+	};
+}
+
+export function escapeLayerState(props: EscapeLayerStateProps) {
+	return new EscapeLayerState(props);
+}
+
+function isResponsibleEscapeLayer(instance: EscapeLayerState) {
+	const layersArr = [...layers];
+	/**
+	 * We first check if we can find a top layer with `close` or `ignore`.
+	 * If that top layer was found and matches the provided node, then the node is
+	 * responsible for the escape. Otherwise, we know that all layers defer so
+	 * the first layer is the responsible one.
+	 */
+	const topMostLayer = layersArr.findLast(
+		([_, { value: behaviorType }]) => behaviorType === "close" || behaviorType === "ignore"
+	);
+	if (topMostLayer) return topMostLayer[0] === instance;
+	const [firstLayerNode] = layersArr[0]!;
+	return firstLayerNode === instance;
+}
diff --git a/packages/bits-ui/src/lib/bits/utilities/escape-layer/index.ts b/packages/bits-ui/src/lib/bits/utilities/escape-layer/index.ts
new file mode 100644
index 000000000..18e7fd7dd
--- /dev/null
+++ b/packages/bits-ui/src/lib/bits/utilities/escape-layer/index.ts
@@ -0,0 +1,3 @@
+export { default as Root } from "./escape-layer.svelte";
+
+export type { EscapeLayerProps as Props } from "./types.js";
diff --git a/packages/bits-ui/src/lib/bits/utilities/escape-layer/types.ts b/packages/bits-ui/src/lib/bits/utilities/escape-layer/types.ts
new file mode 100644
index 000000000..59f21dc40
--- /dev/null
+++ b/packages/bits-ui/src/lib/bits/utilities/escape-layer/types.ts
@@ -0,0 +1,27 @@
+import type { Snippet } from "svelte";
+
+export type EscapeBehaviorType =
+	| "close"
+	| "defer-otherwise-close"
+	| "defer-otherwise-ignore"
+	| "ignore";
+
+export type EscapeLayerProps = {
+	children?: Snippet;
+
+	/**
+	 * Callback fired when escape is pressed.
+	 */
+	onEscape?: (e: KeyboardEvent) => void;
+
+	/**
+	 * Escape behavior type.
+	 * `close`: Closes the element immediately.
+	 * `defer-otherwise-close`: Delegates the action to the parent element. If no parent is found, it closes the element.
+	 * `defer-otherwise-ignore`: Delegates the action to the parent element. If no parent is found, nothing is done.
+	 * `ignore`: Prevents the element from closing and also blocks the parent element from closing in response to an escape key press.
+	 *
+	 * @defaultValue `close`
+	 */
+	behaviorType?: EscapeBehaviorType;
+};