frontend/src/components/NoteEditor.vue

@@ -10,6 +10,14 @@ import { takeMorphOrigin } from "../composables/useEditorMorph";
 import { prefersReducedMotion } from "../composables/useReducedMotion";
 import type { Note, NoteLabel, NoteRevision } from "../stores/notes";
 import { LABEL_CHIP_CLASSES, type NoteColor } from "../notes/colors";
+import {
+  afterEnter,
+  type EditorBlock,
+  joinBlocks,
+  plusTask,
+  splitBlocks,
+  withoutIndex,
+} from "../notes/blocks";
 
 // One modal editor for BOTH composing and editing — a single surface (the board's
 // "Take a note…" bar just opens this in compose mode). `note` = the note being edited,
@@ -24,7 +32,14 @@ const emit = defineEmits<{ (e: "close"): void; (e: "navigate", id: string): void
 const notes = useNotesStore();
 
 const noteId = ref<string | null>(props.note?.id ?? null);
-const body = ref(props.note?.body ?? props.initialBody);
+// BLOCKS rather than one string, because a checklist item is drawn as a real checkbox
+// and a widget cannot live inside a <textarea>. The note is still one markdown body —
+// see notes/blocks.ts — and `body` is what every save, baseline and draft still reads.
+const blocks = ref<EditorBlock[]>(splitBlocks(props.note?.body ?? props.initialBody));
+const body = computed(() => joinBlocks(blocks.value));
+function setBody(text: string): void {
+  blocks.value = splitBlocks(text);
+}
 const color = ref<NoteColor>(props.note?.color ?? "default");
 const labelList = ref<NoteLabel[]>(props.note ? [...props.note.labels] : []);
 // Whether this editor is showing the checklist. A note HAS a checklist (M13 step 2)
@@ -32,7 +47,34 @@ const labelList = ref<NoteLabel[]>(props.note ? [...props.note.labels] : []);
 // on when the note already carries items, and when someone asks for one.
 const saving = ref(false);
 const root = ref<HTMLElement | null>(null);
-const bodyInput = ref<HTMLTextAreaElement | null>(null);
+// One element per block, keyed by the block's id — the only thing about a block that
+// survives one being inserted above it. Focus is asked for by id and honoured after
+// the render that created the field, since an element that does not exist yet cannot
+// take it.
+const blockEls = new Map<number, HTMLTextAreaElement | HTMLInputElement>();
+function setBlockEl(id: number, el: unknown): void {
+  if (el) blockEls.set(id, el as HTMLTextAreaElement);
+  else blockEls.delete(id);
+}
+async function focusBlock(id: number | null): Promise<void> {
+  if (id === null) return;
+  await nextTick();
+  const el = blockEls.get(id);
+  el?.focus();
+  if (el) el.selectionStart = el.selectionEnd = el.value.length;
+}
+
+/** A prose field sized to its text. `rows="1"` plus this beats guessing a row count,
+ *  which is wrong the moment a line wraps. */
+function grow(el: HTMLTextAreaElement): void {
+  el.style.height = "auto";
+  el.style.height = `${el.scrollHeight}px`;
+}
+function growAll(): void {
+  for (const el of blockEls.values()) {
+    if (el instanceof HTMLTextAreaElement) grow(el);
+  }
+}
 const fileInput = ref<HTMLInputElement | null>(null);
 const uploadError = ref("");
 
@@ -80,7 +122,7 @@ watch(
   () => props.note,
   (n) => {
     noteId.value = n?.id ?? null;
-    body.value = n?.body ?? "";
+    setBody(n?.body ?? "");
     color.value = (n?.color ?? "default") as NoteColor;
     labelList.value = n ? [...n.labels] : [];
     baseline.value = { body: n?.body ?? "", color: (n?.color ?? "default") as NoteColor };
@@ -131,7 +173,7 @@ async function flush(): Promise<void> {
 
 function resetCompose(): void {
   noteId.value = null;
-  body.value = "";
+  setBody("");
   color.value = "default";
   labelList.value = [];
   baseline.value = { body: "", color: "default" };
@@ -145,7 +187,9 @@ async function commitAndContinue(): Promise<void> {
   await flush();
   resetCompose();
   await nextTick();
-  bodyInput.value?.focus();
+  growAll();
+  const first = blocks.value[0];
+  await focusBlock(first ? first.id : null);
 }
 // ---- open/close animation (M7) ----
 //
@@ -215,53 +259,66 @@ function onBackdropMousedown(): void {
 
 onMounted(async () => {
   await nextTick();
-  const el = bodyInput.value;
-  el?.focus();
-  // Put the caret after any seeded text (type-to-compose) so typing continues cleanly.
-  if (el) el.selectionStart = el.selectionEnd = el.value.length;
+  growAll();
+  // The LAST block, with the caret after its text: opening a note means continuing it,
+  // and type-to-compose seeds text that should be typed straight on from.
+  const last = blocks.value[blocks.value.length - 1];
+  await focusBlock(last ? last.id : null);
 });
 
-// The same grammar as notes/markdown.ts, narrowed to one line so the pieces can be
-// put back. See that file for why three implementations of it exist.
-const TASK_LINE_RE = /^(\s*)([-*]) +\[([ xX])\](?: +(.*))?$/;
+/** Editing one block: replace its text, leave every other block alone. */
+function setText(index: number, text: string): void {
+  const out = [...blocks.value];
+  out[index] = { ...out[index], text };
+  blocks.value = out;
+}
 
-function onBodyKeydown(e: KeyboardEvent) {
-  // Compose: Shift+Enter saves the note and starts a fresh one (rapid capture).
+function setChecked(index: number, checked: boolean): void {
+  const out = [...blocks.value];
+  out[index] = { ...out[index], checked };
+  blocks.value = out;
+}
+
+function onProseInput(index: number, e: Event): void {
+  const el = e.target as HTMLTextAreaElement;
+  setText(index, el.value);
+  grow(el);
+}
+
+/** Compose: Shift+Enter saves the note and starts a fresh one (rapid capture). */
+function onProseKeydown(e: KeyboardEvent): void {
   if (isCreate.value && e.key === "Enter" && e.shiftKey) {
     e.preventDefault();
     void commitAndContinue();
-    return;
   }
+}
 
-  // Enter on a task line starts the next one; on an EMPTY task line it clears the
-  // marker instead. Both halves are needed — without the second, a list would be
-  // impossible to get out of without deleting characters by hand.
-  if (e.key !== "Enter" || e.shiftKey || e.ctrlKey || e.metaKey || e.altKey) return;
-  const el = e.target as HTMLTextAreaElement;
-  const start = el.selectionStart ?? 0;
-  // A selection means Enter is replacing something; let the browser do it.
-  if (start !== el.selectionEnd) return;
-  const before = body.value.slice(0, start);
-  const rest = body.value.slice(start);
-  // Only at the END of a line. Mid-line, Enter splits the line, which is what anyone
-  // pressing it there meant.
-  if (rest !== "" && !rest.startsWith("\n")) return;
-  const lineStart = before.lastIndexOf("\n") + 1;
-  const match = TASK_LINE_RE.exec(before.slice(lineStart));
-  if (!match) return;
+/** Enter on an item makes the next one; on an EMPTY item it ends the list. */
+function onTaskEnter(index: number): void {
+  const next = afterEnter(blocks.value, index);
+  blocks.value = next.blocks;
+  void focusBlock(next.focus);
+}
 
+/**
+ * Backspace at the very start of an EMPTY item removes it.
+ *
+ * Worth having on the web where Android's is not: a browser sends a real keydown for
+ * Backspace, while an Android soft keyboard sends an IME delete that never surfaces as
+ * one. Enter-on-empty ends a list on both surfaces; this is the extra way out that
+ * only one of them can offer.
+ */
+function onTaskBackspace(index: number, e: KeyboardEvent): void {
+  const el = e.target as HTMLInputElement;
+  if (el.value !== "" || el.selectionStart !== 0) return;
   e.preventDefault();
-  if (!(match[4] ?? "").trim()) {
-    body.value = body.value.slice(0, lineStart) + rest;
-    void nextTick(() => el.setSelectionRange(lineStart, lineStart));
-    return;
-  }
-  // The bullet and indent are carried over, not normalised: continuing someone's
-  // `*` list with a `-` would be an edit they did not ask for.
-  const marker = `${match[1]}${match[2]} [ ] `;
-  body.value = `${before}\n${marker}${rest}`;
-  const caret = start + 1 + marker.length;
-  void nextTick(() => el.setSelectionRange(caret, caret));
+  removeBlock(index);
+}
+
+function removeBlock(index: number): void {
+  const next = withoutIndex(blocks.value, index);
+  blocks.value = next.blocks;
+  void focusBlock(next.focus);
 }
 
 // ---- reminder ----
@@ -307,27 +364,17 @@ function labelChip(c: string): string {
 
 // ---- add a checklist ----
 //
-// Inserts `- [ ] ` at the caret. That is the whole action now: a checklist is lines of
-// the body (M304), so unlike every other toolbar button this one needs NO persisted
-// note to hang anything off — `ensureDraft` is gone from it, and it works on an empty
-// compose box the moment it opens.
-async function addChecklist() {
-  const el = bodyInput.value;
-  const marker = "- [ ] ";
-  if (!el) {
-    body.value = body.value ? `${body.value.replace(/\n+$/, "")}\n${marker}` : marker;
-    return;
-  }
-  const start = el.selectionStart ?? body.value.length;
-  const before = body.value.slice(0, start);
-  // Start a new line unless the caret already sits at the beginning of one — a marker
-  // in the middle of a sentence is not a list item, it is a typo.
-  const prefix = before === "" || before.endsWith("\n") ? "" : "\n";
-  body.value = `${before}${prefix}${marker}${body.value.slice(start)}`;
-  const caret = start + prefix.length + marker.length;
-  await nextTick();
-  el.focus();
-  el.setSelectionRange(caret, caret);
+// Appends an empty item and puts the caret in it. Unlike every other toolbar button
+// this one needs NO persisted note to hang anything off — a checklist is part of the
+// body (M304), so it works on an empty compose box the moment it opens.
+//
+// Appends rather than inserting at the caret because a block editor has no single
+// caret to insert at: the field that had focus may not be the one being looked at by
+// the time this runs.
+function addChecklist(): void {
+  const next = plusTask(blocks.value);
+  blocks.value = next.blocks;
+  void focusBlock(next.focus);
 }
 
 // ---- attachments ----
@@ -406,7 +453,7 @@ async function restoreRevisionAt(revId: string) {
   const id = noteId.value;
   if (!id) return;
   const updated = await notes.restoreRevision(id, revId);
-  body.value = updated.body;
+  setBody(updated.body);
   color.value = updated.color;
   baseline.value = { body: updated.body, color: updated.color };
   void loadRevisions(); // the pre-restore state became a new revision
@@ -509,14 +556,50 @@ function revPreview(rev: NoteRevision): string {
           />
         </div>
 
-        <textarea
-          ref="bodyInput"
-          v-model="body"
-          rows="8"
-          :placeholder="bodyPlaceholder"
-          class="w-full resize-none bg-transparent text-sm leading-relaxed outline-none placeholder:text-neutral-400"
-          @keydown="onBodyKeydown"
-        />
+        <!-- The body, as fields and checkboxes rather than as markup. A checklist
+             item is a real input; a run of prose is one textarea, so typing a
+             paragraph still feels like typing a paragraph. -->
+        <div class="flex flex-col gap-1">
+          <template v-for="(block, i) in blocks" :key="block.id">
+            <div v-if="block.checked !== null" class="group/item flex items-center gap-2">
+              <input
+                type="checkbox"
+                class="h-4 w-4 shrink-0 accent-brand"
+                :checked="block.checked"
+                :aria-label="block.text || 'Checklist item'"
+                @change="setChecked(i, ($event.target as HTMLInputElement).checked)"
+              />
+              <input
+                :ref="(el) => setBlockEl(block.id, el)"
+                :value="block.text"
+                type="text"
+                class="min-w-0 flex-1 bg-transparent text-sm leading-relaxed outline-none"
+                :class="block.checked ? 'text-neutral-400 line-through' : ''"
+                @input="setText(i, ($event.target as HTMLInputElement).value)"
+                @keydown.enter.prevent="onTaskEnter(i)"
+                @keydown.backspace="onTaskBackspace(i, $event)"
+              />
+              <button
+                type="button"
+                class="hover-reveal shrink-0 text-neutral-300 opacity-0 hover:text-neutral-600 focus:opacity-100 group-hover/item:opacity-100 dark:hover:text-neutral-200"
+                aria-label="Delete item"
+                @click="removeBlock(i)"
+              >
+                ×
+              </button>
+            </div>
+            <textarea
+              v-else
+              :ref="(el) => setBlockEl(block.id, el)"
+              :value="block.text"
+              rows="1"
+              :placeholder="i === 0 ? bodyPlaceholder : ''"
+              class="w-full resize-none overflow-hidden bg-transparent text-sm leading-relaxed outline-none placeholder:text-neutral-400"
+              @input="onProseInput(i, $event)"
+              @keydown="onProseKeydown"
+            />
+          </template>
+        </div>
         <!-- No checklist component. The items are lines of the textarea above, which
              is what lets a list sit between two paragraphs (M304). -->
 

frontend/src/notes/blocks.ts

@@ -0,0 +1,110 @@
+// The editor's shape for a note body: a list of blocks rather than one string.
+//
+// The note is still one markdown body underneath (M304) — this is a rendering and
+// input shape, and nothing below the editor can tell it exists. `joinBlocks` puts the
+// string back together on every edit, and for a body already in canonical form it
+// returns exactly what `splitBlocks` was handed.
+//
+// Why blocks at all: a checklist item has to be a real `<input type="checkbox">`, and
+// a widget cannot live inside a `<textarea>`. Only a `contenteditable` could hold one,
+// and that is a different editor with a different set of problems.
+//
+// A run of prose lines is ONE block, not one per line. Typing a paragraph has to feel
+// like typing a paragraph, and a separate field under every sentence would break the
+// caret mid-sentence. Only a checklist item earns a block, because only a checklist
+// item needs a widget.
+//
+// The mirror of android/.../ui/EditorBlock.kt, deliberately: the two editors should
+// behave the same, and the cheapest way to keep them that way is for the shapes to
+// read alike.
+
+import { parseTaskLine, renderTaskLine } from "./markdown";
+
+export interface EditorBlock {
+  /** Stable across edits, so Vue keeps a field's caret when a block is inserted above
+   *  it. Content cannot serve as the key — two empty items are identical and neither
+   *  is the other. */
+  id: number;
+  text: string;
+  /** null for prose; ticked-or-not for a checklist item. */
+  checked: boolean | null;
+}
+
+/** Split a body into blocks, numbering them from `firstId`. */
+export function splitBlocks(body: string, firstId = 0): EditorBlock[] {
+  const out: EditorBlock[] = [];
+  const prose: string[] = [];
+  let id = firstId;
+
+  const flushProse = () => {
+    if (prose.length) {
+      out.push({ id: id++, text: prose.join("\n"), checked: null });
+      prose.length = 0;
+    }
+  };
+
+  for (const line of (body ?? "").split("\n")) {
+    const task = parseTaskLine(line);
+    if (task) {
+      flushProse();
+      out.push({ id: id++, text: task.text, checked: task.checked });
+    } else {
+      prose.push(line);
+    }
+  }
+  flushProse();
+
+  // Never empty: an empty note still needs one field to type into.
+  return out.length ? out : [{ id, text: "", checked: null }];
+}
+
+/** The body those blocks stand for. */
+export function joinBlocks(blocks: EditorBlock[]): string {
+  return blocks.map((b) => (b.checked === null ? b.text : renderTaskLine(b.text, b.checked))).join("\n");
+}
+
+/** An id nothing else is using. Monotonic within a session, which is all it has to be. */
+export function nextId(blocks: EditorBlock[]): number {
+  return blocks.reduce((max, b) => Math.max(max, b.id), -1) + 1;
+}
+
+/**
+ * What Enter does on a checklist item, and which block should hold the caret after.
+ *
+ * On an item with words in it, a new empty item below. On an EMPTY one, the item
+ * becomes prose — which is how a list ENDS, and the only way to get a paragraph after
+ * one. Without that half a list is impossible to get out of.
+ *
+ * Appends rather than splitting at the caret: splitting an item in two is a rarity,
+ * and the caret is at the end for every ordinary use of that key.
+ */
+export function afterEnter(blocks: EditorBlock[], index: number): { blocks: EditorBlock[]; focus: number } {
+  const block = blocks[index];
+  const out = [...blocks];
+  if (!block.text.trim()) {
+    out[index] = { ...block, text: "", checked: null };
+    return { blocks: out, focus: block.id };
+  }
+  const id = nextId(blocks);
+  out.splice(index + 1, 0, { id, text: "", checked: false });
+  return { blocks: out, focus: id };
+}
+
+/**
+ * Drop a block, leaving at least one field to type into.
+ *
+ * Focus goes to the block above — or, when the first one was removed, to whichever
+ * takes its place. `index - 1` alone is -1 there, which would leave nothing focused.
+ */
+export function withoutIndex(blocks: EditorBlock[], index: number): { blocks: EditorBlock[]; focus: number | null } {
+  const kept = blocks.filter((_, i) => i !== index);
+  const fallback: EditorBlock[] = [{ id: nextId(blocks), text: "", checked: null }];
+  const remaining = kept.length ? kept : fallback;
+  return { blocks: remaining, focus: remaining[Math.max(0, index - 1)]?.id ?? null };
+}
+
+/** One more empty checklist item at the end, and the id to put the caret in. */
+export function plusTask(blocks: EditorBlock[]): { blocks: EditorBlock[]; focus: number } {
+  const id = nextId(blocks);
+  return { blocks: [...blocks, { id, text: "", checked: false }], focus: id };
+}

frontend/src/notes/markdown.ts

@@ -66,6 +66,27 @@ export function parseInline(text: string): InlineToken[] {
 // which is at least consistent.
 const TASK_RE = /^\s*[-*] +\[([ xX])\](?: +(.*))?$/;
 
+export interface TaskLine {
+  checked: boolean;
+  text: string;
+}
+
+/** One task line's parts, or null when the line is prose.
+ *
+ *  Exported so the EDITOR's block split (notes/blocks.ts) and this read-view parser
+ *  agree by construction rather than by comment. One grammar, one matcher. */
+export function parseTaskLine(line: string): TaskLine | null {
+  const m = TASK_RE.exec(line);
+  return m ? { checked: m[1] !== " ", text: m[2] ?? "" } : null;
+}
+
+/** One item as the body line that stores it, in canonical form — `- [x] `, lowercase,
+ *  and no trailing space when the item is empty so a round trip does not grow it. */
+export function renderTaskLine(text: string, checked: boolean): string {
+  const mark = checked ? "x" : " ";
+  return text ? `- [${mark}] ${text}` : `- [${mark}]`;
+}
+
 export function parseMarkdown(text: string): Block[] {
   const lines = (text ?? "").split("\n");
   const blocks: Block[] = [];
@@ -124,15 +145,15 @@ export function parseMarkdown(text: string): Block[] {
     // Task list, BEFORE the plain bullet below — which would otherwise swallow
     // `- [ ] x` as an ordinary list item and leave the brackets showing. Same
     // ordering reason as `code` being matched before emphasis in INLINE_RE.
-    if (TASK_RE.test(line)) {
+    if (parseTaskLine(line)) {
       flushPara();
       const items: InlineToken[][] = [];
       const tasks: TaskMeta[] = [];
       while (i < lines.length) {
-        const m = TASK_RE.exec(lines[i]);
-        if (!m) break;
-        items.push(parseInline(m[2] ?? ""));
-        tasks.push({ index: taskIndex, checked: m[1] !== " " });
+        const task = parseTaskLine(lines[i]);
+        if (!task) break;
+        items.push(parseInline(task.text));
+        tasks.push({ index: taskIndex, checked: task.checked });
         taskIndex++;
         i++;
       }