From 3308fd4116719c0d9f032fa13e469086bd26f0c1 Mon Sep 17 00:00:00 2001
From: Moritz Bischof <moritz.bischof1@gmail.com>
Date: Mon, 3 May 2021 19:22:37 +0200
Subject: [PATCH] extract ContextMenuInner.svelte

---
 src/ContextMenu/ContextMenu.svelte       | 121 +++-------------------
 src/ContextMenu/ContextMenuInner.svelte  | 126 +++++++++++++++++++++++
 src/ContextMenu/ContextMenuOption.svelte |   9 +-
 3 files changed, 146 insertions(+), 110 deletions(-)
 create mode 100644 src/ContextMenu/ContextMenuInner.svelte

diff --git a/src/ContextMenu/ContextMenu.svelte b/src/ContextMenu/ContextMenu.svelte
index 73f6e581..7c157c8a 100644
--- a/src/ContextMenu/ContextMenu.svelte
+++ b/src/ContextMenu/ContextMenu.svelte
@@ -1,4 +1,6 @@
 <script>
+  import ContextMenuInner from "./ContextMenuInner.svelte";
+
   /**
    * Set to `true` to open the menu
    * Either `x` and `y` must be greater than zero
@@ -14,91 +16,29 @@
   /** Obtain a reference to the unordered list HTML element */
   export let ref = null;
 
-  import {
-    setContext,
-    getContext,
-    afterUpdate,
-    createEventDispatcher,
-  } from "svelte";
-  import { writable } from "svelte/store";
+  import { getContext } from "svelte";
 
-  const dispatch = createEventDispatcher();
-  const position = writable([x, y]);
-  const currentIndex = writable(-1);
-  const hasPopup = writable(false);
   const ctx = getContext("ContextMenu");
 
-  let options = [];
-  let direction = 1;
-  let prevX = 0;
-  let prevY = 0;
-  let focusIndex = -1;
   let level;
+  $: level = !ctx ? 1 : 2;
 
   function close() {
     open = false;
     x = 0;
     y = 0;
-    prevX = 0;
-    prevY = 0;
-    focusIndex = -1;
   }
 
-  setContext("ContextMenu", {
-    currentIndex,
-    position,
-    close,
-    setPopup: (popup) => {
-      hasPopup.set(popup);
-    },
-  });
-
-  afterUpdate(() => {
-    if (open) {
-      options = [...ref.querySelectorAll("li[data-nested='false']")];
-
-      if (level === 1) {
-        if (prevX !== x || prevY !== y) ref.focus();
-        prevX = x;
-        prevY = y;
-      }
-
-      dispatch("open");
-    } else {
-      dispatch("close");
-    }
-
-    if (!$hasPopup && options[focusIndex]) options[focusIndex].focus();
-  });
-
-  $: level = !ctx ? 1 : 2;
-  $: currentIndex.set(focusIndex);
+  function onContextMenu(e) {
+    if (level > 1) return;
+    open = true;
+    x = e.x;
+    y = e.y;
+  }
 </script>
 
 <svelte:window
-  on:contextmenu|preventDefault="{(e) => {
-    if (level > 1) return;
-
-    const { height, width } = ref.getBoundingClientRect();
-
-    if (open || x === 0) {
-      if (window.innerWidth - width < e.x) {
-        x = e.x - width;
-      } else {
-        x = e.x;
-      }
-    }
-
-    if (open || y === 0) {
-      if (window.innerHeight - height < e.y) {
-        y = e.y - height;
-      } else {
-        y = e.y;
-      }
-    }
-    position.set([x, y]);
-    open = true;
-  }}"
+  on:contextmenu|preventDefault="{onContextMenu}"
   on:click="{(e) => {
     if (!open) return;
     if (e.target.contains(ref)) close();
@@ -108,41 +48,6 @@
   }}"
 />
 
-<ul
-  bind:this="{ref}"
-  role="menu"
-  tabindex="-1"
-  data-direction="{direction}"
-  data-level="{level}"
-  class:bx--context-menu="{true}"
-  class:bx--context-menu--open="{open}"
-  class:bx--context-menu--invisible="{open && x === 0 && y === 0}"
-  class:bx--context-menu--root="{level === 1}"
-  {...$$restProps}
-  style="left: {x}px; top: {y}px; {$$restProps.style}"
-  on:click
-  on:click="{({ target }) => {
-    const closestOption = target.closest('[tabindex]');
-
-    if (closestOption && closestOption.getAttribute('role') !== 'menuitem') {
-      close();
-    }
-  }}"
-  on:keydown
-  on:keydown="{(e) => {
-    if (open) e.preventDefault();
-    if ($hasPopup) return;
-
-    if (e.key === 'ArrowDown') {
-      if (focusIndex < options.length - 1) focusIndex++;
-    } else if (e.key === 'ArrowUp') {
-      if (focusIndex === -1) {
-        focusIndex = options.length - 1;
-      } else {
-        if (focusIndex > 0) focusIndex--;
-      }
-    }
-  }}"
->
+<ContextMenuInner bind:open bind:ref x="{x}" y="{y}">
   <slot />
-</ul>
+</ContextMenuInner>
diff --git a/src/ContextMenu/ContextMenuInner.svelte b/src/ContextMenu/ContextMenuInner.svelte
new file mode 100644
index 00000000..9376100c
--- /dev/null
+++ b/src/ContextMenu/ContextMenuInner.svelte
@@ -0,0 +1,126 @@
+<script>
+  /**
+   * Set to `true` to open the menu
+   * Either `x` and `y` must be greater than zero
+   */
+  export let open = false;
+
+  /** Specify the horizontal offset of the menu position */
+  export let x = 0;
+
+  /** Specify the vertical offset of the menu position */
+  export let y = 0;
+
+  /** Obtain a reference to the unordered list HTML element */
+  export let ref = null;
+
+  import {
+    setContext,
+    getContext,
+    afterUpdate,
+    createEventDispatcher,
+  } from "svelte";
+  import { writable } from "svelte/store";
+
+  const dispatch = createEventDispatcher();
+  const position = writable([x, y]);
+  const dimensions = writable([0, 0]);
+  const currentIndex = writable(-1);
+  const hasPopup = writable(false);
+  const ctx = getContext("ContextMenu");
+
+  let options = [];
+  let direction = 1;
+  let prevX = 0;
+  let prevY = 0;
+  let focusIndex = -1;
+  let level;
+
+  $: level = !ctx ? 1 : 2;
+  $: $position = [x, y];
+  $: $currentIndex = focusIndex;
+  $: if (open && level === 1 && ref != null) {
+    const { height, width } = ref.getBoundingClientRect();
+    $dimensions = [width, height];
+
+    // if the menu is too far to the right, display it on the left side of the cursor
+    if (window.innerWidth - width < x) x -= width;
+
+    // if the menu is too far down, display it above the cursor
+    if (window.innerHeight - height < y) y -= height;
+  }
+
+  function close() {
+    open = false;
+    x = 0;
+    y = 0;
+    prevX = 0;
+    prevY = 0;
+    focusIndex = -1;
+  }
+
+  setContext("ContextMenu", {
+    currentIndex,
+    position,
+    dimensions,
+    close,
+    setPopup: (popup) => ($hasPopup = popup),
+  });
+
+  afterUpdate(() => {
+    if (open) {
+      options = [...ref.querySelectorAll("li[data-nested='false']")];
+
+      if (level === 1) {
+        if (prevX !== x || prevY !== y) ref.focus();
+        prevX = x;
+        prevY = y;
+      }
+
+      dispatch("open");
+    } else {
+      dispatch("close");
+    }
+
+    if (!$hasPopup && options[focusIndex]) options[focusIndex].focus();
+  });
+</script>
+
+<ul
+  bind:this="{ref}"
+  role="menu"
+  tabindex="-1"
+  data-direction="{direction}"
+  data-level="{level}"
+  class:bx--context-menu="{true}"
+  class:bx--context-menu--open="{open}"
+  class:bx--context-menu--invisible="{open && x === 0 && y === 0}"
+  class:bx--context-menu--root="{level === 1}"
+  {...$$restProps}
+  style="left: {x}px; top: {y}px; {$$restProps.style}"
+  on:click
+  on:click="{({ target }) => {
+    const closestOption = target.closest('[tabindex]');
+
+    if (closestOption && closestOption.getAttribute('role') !== 'menuitem') {
+      close();
+    }
+  }}"
+  on:keydown
+  on:keydown="{(e) => {
+    if (open) e.preventDefault();
+    if ($hasPopup) return;
+
+    if (e.key === 'ArrowDown') {
+      if (focusIndex < options.length - 1) focusIndex++;
+    } else if (e.key === 'ArrowUp') {
+      if (focusIndex === -1) {
+        focusIndex = options.length - 1;
+      } else {
+        if (focusIndex > 0) focusIndex--;
+      }
+    }
+  }}"
+>
+  <slot />
+</ul>
diff --git a/src/ContextMenu/ContextMenuOption.svelte b/src/ContextMenu/ContextMenuOption.svelte
index 1c9dbd91..f2452a8d 100644
--- a/src/ContextMenu/ContextMenuOption.svelte
+++ b/src/ContextMenu/ContextMenuOption.svelte
@@ -59,6 +59,7 @@
   const ctxRadioGroup = getContext("ContextMenuRadioGroup");
 
   const rootMenuPosition = ctx.position;
+  const rootMenuDimensions = ctx.dimensions;
 
   // "moderate-01" duration (ms) from Carbon motion recommended for small expansion, short distance movements
   const moderate01 = 150;
@@ -120,11 +121,15 @@
   $: ctx.setPopup(submenuOpen);
   $: if (submenuOpen) {
     const rootMenuX = $rootMenuPosition[0];
+    const rootMenuWidth = $rootMenuDimensions[0];
     const { width, y } = ref.getBoundingClientRect();
-    let x = rootMenuX + width;
 
-    if (window.innerWidth - rootMenuX < width) {
+    let x;
+    if (window.innerWidth < rootMenuX + rootMenuWidth + width) {
+      // submenu is too far to the right,  so we display it on the left side
       x = rootMenuX - width;
+    } else {
+      x = rootMenuX + width;
     }
 
     submenuPosition = [x, y];