Fix #2100: w should not collapse selection in visual mode

src/lib/config.ts

@@ -441,7 +441,7 @@ export class default_config {
             tri.visual.extendByCharacter(sel, "backward");
         `,
         e: 'js tri.dom.getSelection().modify("extend","forward","word")',
-        w: 'js let s=tri.dom.getSelection(); s.modify("extend","forward","word"); s.modify("extend","forward","word"); s.modify("extend","backward","word"); s.modify("extend","forward","character")',
+        w: "js tri.visual.extendByWord(tri.dom.getSelection())",
         b: 'js let s=tri.dom.getSelection(); s.modify("extend","backward","character"); s.modify("extend","backward","word"); s.modify("extend","forward","character")',
         j: 'js tri.dom.getSelection().modify("extend","forward","line")',
         q: "composite js tri.dom.getSelection().toString() | text2qr --timeout 5",

src/lib/visual.test.ts

@@ -0,0 +1,26 @@
+import { extendByWord } from "@src/lib/visual"
+
+test("word movement restores the last selection at its boundary", () => {
+    const node = document.createTextNode("one two")
+    document.body.appendChild(node)
+    const selection = getSelection()
+    selection.setBaseAndExtent(node, 5, node, 1)
+    const focusOffsets = [3, 7, 4, 5]
+    let moves = 0
+    const modify = jest.fn(() => {
+        selection.setBaseAndExtent(node, 5, node, focusOffsets[moves++])
+    })
+    selection.modify = modify
+
+    extendByWord(selection)
+
+    expect(modify.mock.calls).toEqual([
+        ["extend", "forward", "word"],
+        ["extend", "forward", "word"],
+        ["extend", "backward", "word"],
+        ["extend", "forward", "character"],
+    ])
+    expect(selection.isCollapsed).toBe(false)
+    expect(selection.anchorOffset).toBe(5)
+    expect(selection.focusOffset).toBe(4)
+})

src/lib/visual.ts

@@ -57,3 +57,23 @@ export function extendByCharacter(
     reverseSelection(selection)
     selection.modify("extend", direction, "character")
 }
+
+export function extendByWord(selection: Selection): void {
+    if (!selection.focusNode) return
+
+    selection.modify("extend", "forward", "word")
+    selection.modify("extend", "forward", "word")
+    selection.modify("extend", "backward", "word")
+    const oldFocusNode = selection.focusNode
+    const oldFocusOffset = selection.focusOffset
+    const oldAnchorNode = selection.anchorNode
+    const oldAnchorOffset = selection.anchorOffset
+    selection.modify("extend", "forward", "character")
+    if (!selection.isCollapsed) return
+    selection.setBaseAndExtent(
+        oldAnchorNode,
+        oldAnchorOffset,
+        oldFocusNode,
+        oldFocusOffset,
+    )
+}