diff --git a/src/elements/drag-area.ts b/src/elements/drag-area.ts
index 0316cd8..7743cc9 100644
--- a/src/elements/drag-area.ts
+++ b/src/elements/drag-area.ts
@@ -1,7 +1,7 @@
-import { css, CSSResult, html, LitElement, type TemplateResult } from 'lit'
-import { customElement } from 'lit/decorators.js'
-import { cssReset } from '../utils/css-reset.js'
-import { DragLine } from './drag-line.js'
+import {css, CSSResult, html, LitElement, type TemplateResult} from 'lit'
+import {customElement} from 'lit/decorators.js'
+import {cssReset} from '../utils/css-reset.js'
+import {DragLine} from './drag-line.js'
 
 declare global {
   interface HTMLElementEventMap {
@@ -39,17 +39,17 @@ export class DragArea extends LitElement {
 
   #gesture:
     | {
-      /** Set on significant duration or movement. */
-      drag?: true
-      /** Most recent event intercepted. */
-      ev: PointerEvent
-      /** Origin of the opening pointer down event. */
-      readonly start: Readonly<{ x: number; y: number }>
-      /** Re-target all drag events in the gesture. */
-      readonly target: HTMLElement
-      /** Synthetic drag event interval timer. */
-      readonly timer: ReturnType<typeof setInterval>
-    }
+        /** Set on significant duration or movement. */
+        drag?: true
+        /** Most recent event intercepted. */
+        ev: PointerEvent
+        /** Origin of the opening pointer down event. */
+        readonly start: Readonly<{x: number; y: number}>
+        /** Re-target all drag events in the gesture. */
+        readonly target: HTMLElement
+        /** Synthetic drag event interval timer. */
+        readonly timer: ReturnType<typeof setInterval>
+      }
     | undefined
 
   // to-do:  Disable mobile long press?
@@ -74,7 +74,7 @@ export class DragArea extends LitElement {
   #onPointerDown = (ev: PointerEvent): void => {
     if (ev.altKey || ev.ctrlKey || ev.metaKey || ev.shiftKey) return
     if (!ev.isPrimary || ev.buttons !== 1) return
-    if (!ev.composedPath().some((target) => target instanceof DragLine)) return
+    if (!ev.composedPath().some(target => target instanceof DragLine)) return
     const target = ev.composedPath()[0]
     if (!(target instanceof HTMLElement)) return
     if (target.isContentEditable && target.matches(':focus')) return // Editing text.
@@ -82,9 +82,9 @@ export class DragArea extends LitElement {
     ev.preventDefault()
     this.#gesture = {
       ev,
-      start: { x: ev.clientX, y: ev.clientY },
+      start: {x: ev.clientX, y: ev.clientY},
       target,
-      timer: setInterval(() => this.#onPointerMove(this.#gesture!.ev), 10),
+      timer: setInterval(() => this.#onPointerMove(this.#gesture!.ev), 10)
     }
   }
 
diff --git a/src/elements/drag-line.ts b/src/elements/drag-line.ts
index 88f7bba..66676c4 100644
--- a/src/elements/drag-line.ts
+++ b/src/elements/drag-line.ts
@@ -1,18 +1,18 @@
-import { css, CSSResult, html, LitElement, type TemplateResult } from 'lit'
-import { customElement } from 'lit/decorators.js'
-import type { Group, Line, PositionLine } from '../tree/text-tree.js'
-import { Bubble } from '../utils/bubble.js'
-import { cssReset } from '../utils/css-reset.js'
+import {css, CSSResult, html, LitElement, type TemplateResult} from 'lit'
+import {customElement} from 'lit/decorators.js'
+import type {Group, Line, PositionLine} from '../tree/text-tree.js'
+import {Bubble} from '../utils/bubble.js'
+import {cssReset} from '../utils/css-reset.js'
 import {
   blurActiveElement,
   composedAncestorElement,
   composedClosest,
   composedClosestScrollable,
   composedElementFromPoint,
-  scrollTowardsEdge,
+  scrollTowardsEdge
 } from '../utils/element-util.js'
-import type { LineElement } from './line-element.js'
-import { LineList } from './line-list.js'
+import type {LineElement} from './line-element.js'
+import {LineList} from './line-list.js'
 
 export type DragEnd = {
   readonly from: Readonly<Line>
@@ -53,14 +53,14 @@ export class DragLine extends LitElement {
 
   #drag:
     | {
-      /** Cursor position relative this. */
-      readonly cursor: Readonly<{ x: number; y: number }>
-      /** A clone of this modified to follow the cursor. */
-      readonly ghost: DragLine
-      readonly line: Readonly<Line>
-      over?: { at: PositionLine; line: Readonly<Line> }
-      parent: Element
-    }
+        /** Cursor position relative this. */
+        readonly cursor: Readonly<{x: number; y: number}>
+        /** A clone of this modified to follow the cursor. */
+        readonly ghost: DragLine
+        readonly line: Readonly<Line>
+        over?: {at: PositionLine; line: Readonly<Line>}
+        parent: Element
+      }
     | undefined
 
   constructor() {
@@ -87,8 +87,8 @@ export class DragLine extends LitElement {
         Bubble<DragEnd>('drag-line-end', {
           from: this.#drag.line,
           to: this.#drag.over.line,
-          at: this.#drag.over.at,
-        }),
+          at: this.#drag.over.at
+        })
       )
       // Lit components track children rendered from the model. Manually adding
       // or removing a child may cause a duplicate or missing child on model
@@ -96,11 +96,9 @@ export class DragLine extends LitElement {
       // parent lists it was associated with.
 
       this.#drag.parent.dispatchEvent(
-        Bubble<undefined>('drag-line-invalidate', undefined),
-      )
-      this.dispatchEvent(
-        Bubble<undefined>('drag-line-invalidate', undefined),
+        Bubble<undefined>('drag-line-invalidate', undefined)
       )
+      this.dispatchEvent(Bubble<undefined>('drag-line-invalidate', undefined))
       this.remove()
       this.#drag = undefined
     }
@@ -116,19 +114,18 @@ export class DragLine extends LitElement {
     this.#moveGhostToCursor(scrollable, ev)
 
     if (scrollable) {
-      scrollTowardsEdge(scrollable, { x: ev.clientX, y: ev.clientY }, 32, 4)
+      scrollTowardsEdge(scrollable, {x: ev.clientX, y: ev.clientY}, 32, 4)
     }
 
     const el = composedElementFromPoint(ev.pageX, ev.pageY)
     if (!el) return
 
-    const over = <DragLine | LineList | undefined> (
+    const over = <DragLine | LineList | undefined>(
       composedClosest('drag-line, line-list', el)
     )
     if (!over) return
-    const overLine = over instanceof DragLine
-      ? queryLineElement(over)?.line
-      : undefined // to-do: fix for list
+    const overLine =
+      over instanceof DragLine ? queryLineElement(over)?.line : undefined // to-do: fix for list
     if (!overLine) return
 
     let op = computeDragOp(ev, this, over)
@@ -157,7 +154,7 @@ export class DragLine extends LitElement {
         op satisfies 'none'
         return
     }
-    this.#drag.over = { at, line: overLine }
+    this.#drag.over = {at, line: overLine}
   }
 
   #onDragStart = (ev: DragEvent): void => {
@@ -172,18 +169,17 @@ export class DragLine extends LitElement {
     if (!parent) throw Error('missing parent')
 
     this.#drag = {
-      cursor: { x: ev.offsetX, y: ev.offsetY },
-      ghost: <DragLine> this.cloneNode(true), // Before add('picked') and follow.
+      cursor: {x: ev.offsetX, y: ev.offsetY},
+      ghost: <DragLine>this.cloneNode(true), // Before add('picked') and follow.
       line: lineEl.line,
-      parent: parent,
+      parent: parent
     }
 
     this.classList.add('picked')
     lineEl.classList.add('picked')
 
     if (this.#drag.ghost.children[0]) {
-      ;(<Element & { line: Line }> this.#drag.ghost.children[0]).line =
-        lineEl.line
+      ;(<Element & {line: Line}>this.#drag.ghost.children[0]).line = lineEl.line
       this.#drag.ghost.children[0].classList.add('ghost')
       // setTimeout(() => this.#drag.ghost.children[0].classList.add('ghost'), 10)
     }
@@ -202,15 +198,15 @@ export class DragLine extends LitElement {
       0,
       Math.min(
         scrollable.scrollLeft + ev.pageX - this.#drag.cursor.x,
-        scrollable.scrollWidth - rect.width - 1,
-      ),
+        scrollable.scrollWidth - rect.width - 1
+      )
     )
     const y = Math.max(
       0,
       Math.min(
         scrollable.scrollTop + ev.pageY - this.#drag.cursor.y,
-        scrollable.scrollHeight - rect.height - 1,
-      ),
+        scrollable.scrollHeight - rect.height - 1
+      )
     )
     this.#drag.ghost.style.translate = `${x}px ${y}px`
   }
@@ -223,7 +219,7 @@ export class DragLine extends LitElement {
 function computeDragOp(
   ev: DragEvent,
   picked: DragLine,
-  over: DragLine | LineList,
+  over: DragLine | LineList
 ): 'none' | 'after' | 'append' | 'before' | 'prepend' {
   if (over.contains(picked)) return 'none' // Pivoting over picked may oscillate.
   if (over instanceof LineList) return 'append'
@@ -232,7 +228,7 @@ function computeDragOp(
   if (!lineEl) return 'none'
 
   const rect = lineEl.rect
-  const offset = { x: ev.pageX - rect.x, y: ev.pageY - rect.y }
+  const offset = {x: ev.pageX - rect.x, y: ev.pageY - rect.y}
 
   const above = offset.y / rect.height < 0.5
   const inside = offset.x / rect.width >= 0.5
@@ -246,6 +242,5 @@ function computeDragOp(
 }
 
 function queryLineElement(el: LitElement): LineElement | undefined {
-  return <LineElement> el.renderRoot.querySelector('slot')!
-    .assignedElements()[0]
+  return <LineElement>el.renderRoot.querySelector('slot')!.assignedElements()[0]
 }
diff --git a/src/elements/line-element.ts b/src/elements/line-element.ts
index 0793cba..9a91089 100644
--- a/src/elements/line-element.ts
+++ b/src/elements/line-element.ts
@@ -1,5 +1,5 @@
-import type { LitElement } from 'lit'
-import type { Line } from '../tree/text-tree.js'
+import type {LitElement} from 'lit'
+import type {Line} from '../tree/text-tree.js'
 
 export type LineElement = LitElement & {
   line?: Readonly<Line> | undefined
diff --git a/src/elements/linear-text/linear-text-vars.ts b/src/elements/linear-text/linear-text-vars.ts
index 6489c3a..74ded64 100644
--- a/src/elements/linear-text/linear-text-vars.ts
+++ b/src/elements/linear-text/linear-text-vars.ts
@@ -1,4 +1,4 @@
-import { css, type CSSResult } from 'lit'
+import {css, type CSSResult} from 'lit'
 
 export const linearTextVars: CSSResult = css`
   :host {
diff --git a/src/io/file.ts b/src/io/file.ts
index 685b751..d57d7e4 100644
--- a/src/io/file.ts
+++ b/src/io/file.ts
@@ -1,4 +1,4 @@
-import { fileOpen, fileSave } from 'browser-fs-access'
+import {fileOpen, fileSave} from 'browser-fs-access'
 
 export type FileAndHandle = {
   file: File
@@ -15,45 +15,45 @@ export async function openFile(): Promise<FileAndHandle | undefined> {
     file = await fileOpen({
       mimeTypes: [defaultMimeType],
       extensions: [...defaultExtensions],
-      description: 'Plain Text Files',
+      description: 'Plain Text Files'
     })
   } catch (err) {
     if (isCanceledByUser(err)) return
     throw err
   }
-  return { file, handle: file.handle }
+  return {file, handle: file.handle}
 }
 
 export async function reopenFile(
-  fileAndHandle: FileAndHandle,
+  fileAndHandle: FileAndHandle
 ): Promise<FileAndHandle> {
   if (!fileAndHandle.handle) return fileAndHandle
   return {
     file: await fileAndHandle.handle.getFile(),
-    handle: fileAndHandle.handle,
+    handle: fileAndHandle.handle
   }
 }
 
 export function isFileModified(
   before: Readonly<FileAndHandle>,
-  after: Readonly<FileAndHandle>,
+  after: Readonly<FileAndHandle>
 ): boolean {
   return before.file.lastModified < after.file.lastModified
 }
 
 export async function saveFile(
   fileAndHandle: FileAndHandle | undefined,
-  text: string,
+  text: string
 ): Promise<FileAndHandle | undefined> {
   let handle
   try {
     handle = await fileSave(
-      new Blob([text], { type: defaultMimeType }),
+      new Blob([text], {type: defaultMimeType}),
       {
         fileName: fileAndHandle?.file.name ?? `untitled${defaultExtension}`,
-        extensions: [...defaultExtensions],
+        extensions: [...defaultExtensions]
       },
-      fileAndHandle?.handle,
+      fileAndHandle?.handle
     )
   } catch (err) {
     if (isCanceledByUser(err)) {
@@ -63,7 +63,7 @@ export async function saveFile(
     throw err
   }
   if (!handle) return fileAndHandle
-  return { file: await handle.getFile(), handle }
+  return {file: await handle.getFile(), handle}
 }
 
 function isCanceledByUser(err: unknown): boolean {
diff --git a/src/io/storage.ts b/src/io/storage.ts
index 51eff3f..cf6ee93 100644
--- a/src/io/storage.ts
+++ b/src/io/storage.ts
@@ -1,4 +1,4 @@
-import { TextTree } from '../tree/text-tree.js'
+import {TextTree} from '../tree/text-tree.js'
 
 export type Autosave = {
   /** Filename last saved as. */
@@ -18,13 +18,13 @@ const autosave: string = 'linearText'
 export function saveStorage(
   filename: string | undefined,
   saved: boolean,
-  tree: Readonly<TextTree>,
+  tree: Readonly<TextTree>
 ): void {
   const save: Autosave = {
     filename,
     saved,
     text: TextTree.toString(tree),
-    version: 1,
+    version: 1
   }
   localStorage.setItem(autosave, JSON.stringify(save))
 }
diff --git a/src/manifest.json b/src/manifest.json
index 9e12da9..2f6f966 100644
--- a/src/manifest.json
+++ b/src/manifest.json
@@ -4,21 +4,13 @@
   "display": "standalone",
   "homepage_url": "https://lineartext.com",
   "icons": [
-    { "src": "favicon/favicon.png", "sizes": "16x16", "type": "image/png" },
-    { "src": "favicon/favicon32.png", "sizes": "32x32", "type": "image/png" },
-    { "src": "favicon/favicon48.png", "sizes": "48x48", "type": "image/png" },
-    { "src": "favicon/favicon64.png", "sizes": "64x64", "type": "image/png" },
-    {
-      "src": "favicon/favicon192.png",
-      "sizes": "192x192",
-      "type": "image/png"
-    },
-    {
-      "src": "favicon/favicon512.png",
-      "sizes": "512x512",
-      "type": "image/png"
-    },
-    { "src": "favicon/favicon.svg", "sizes": "any", "type": "image/svg+xml" }
+    {"src": "favicon/favicon.png", "sizes": "16x16", "type": "image/png"},
+    {"src": "favicon/favicon32.png", "sizes": "32x32", "type": "image/png"},
+    {"src": "favicon/favicon48.png", "sizes": "48x48", "type": "image/png"},
+    {"src": "favicon/favicon64.png", "sizes": "64x64", "type": "image/png"},
+    {"src": "favicon/favicon192.png", "sizes": "192x192", "type": "image/png"},
+    {"src": "favicon/favicon512.png", "sizes": "512x512", "type": "image/png"},
+    {"src": "favicon/favicon.svg", "sizes": "any", "type": "image/svg+xml"}
   ],
   "manifest_version": 3,
   "name": "Linear Text",
diff --git a/src/tree/line-type.ts b/src/tree/line-type.ts
index 63081db..810991a 100644
--- a/src/tree/line-type.ts
+++ b/src/tree/line-type.ts
@@ -2,9 +2,9 @@ import {
   isDataImageURIStr,
   isDataURIStr,
   isFileURIStr,
-  isHTTPURIStr,
+  isHTTPURIStr
 } from '../uri-parser/uri-parser.js'
-import { isNumeric } from '../utils/string-util.js'
+import {isNumeric} from '../utils/string-util.js'
 
 /** String-encoded data type of the text value. */
 export type LineType =
@@ -61,11 +61,11 @@ const imageExtensions = Object.freeze([
   '.ico',
   '.cur',
   '.tif',
-  '.tiff',
+  '.tiff'
 ])
 
 function endsWithImageExtension(text: string): boolean {
-  const extIndex = imageExtensions.find((ext) => text.endsWith(ext))
+  const extIndex = imageExtensions.find(ext => text.endsWith(ext))
   if (extIndex == null) return false
   // Require not just an extension but a filename stem too.
   return text.length > extIndex.length
diff --git a/src/tree/text-tree.test.ts b/src/tree/text-tree.test.ts
index f5e46ec..0e8bb8c 100644
--- a/src/tree/text-tree.test.ts
+++ b/src/tree/text-tree.test.ts
@@ -479,9 +479,8 @@ test('multi-line group (2)', () =>
     }
   `))
 test('multi-line groups (3)', () =>
-  expect(
-    TextTree('a\nb\nc\n\nd\ne\nf\n\ng\nh\ni', 2, IDFactory())
-  ).toMatchInlineSnapshot(`
+  expect(TextTree('a\nb\nc\n\nd\ne\nf\n\ng\nh\ni', 2, IDFactory()))
+    .toMatchInlineSnapshot(`
     {
       "down": [
         {
@@ -1085,9 +1084,7 @@ test('an empty line before a group is added to the preceding group (2)', () =>
     }
   `))
 test('an empty line before a group is added to the preceding group (3)', () =>
-  expect(
-    TextTree('a\n\n\n\n\n\nb\n\n', 2, IDFactory())
-  ).toMatchInlineSnapshot(`
+  expect(TextTree('a\n\n\n\n\n\nb\n\n', 2, IDFactory())).toMatchInlineSnapshot(`
     {
       "down": [
         {
diff --git a/src/tree/text-tree.ts b/src/tree/text-tree.ts
index 270e0a6..2f71d1f 100644
--- a/src/tree/text-tree.ts
+++ b/src/tree/text-tree.ts
@@ -1,4 +1,4 @@
-import { treeAdd, treeRemove, treeRoot, treeTouch } from './tree.js'
+import {treeAdd, treeRemove, treeRoot, treeTouch} from './tree.js'
 
 /**
  * End of line; an empty line ("\n" or "\r\n"). These voids are tracked to allow
@@ -88,17 +88,17 @@ const factory: IDFactory = IDFactory()
 export function TextTree(
   str: string,
   indentW: IndentW,
-  id: IDFactory = factory,
+  id: IDFactory = factory
 ): TextTree {
-  const tree: TextTree = { down: [], id: id(), indentW, type: 'TextTree' }
+  const tree: TextTree = {down: [], id: id(), indentW, type: 'TextTree'}
   let prev: Line | undefined
 
-  for (const { start, text, end } of split(str)) {
+  for (const {start, text, end} of split(str)) {
     if (!text && !start) {
       // EOL. Create group if none exists.
-      const group = tree.down.at(-1) ??
-        treeAdd<Group>({ id: id(), type: 'Group' }, tree, -1)
-      treeAdd<EOL>({ id: id(), end, type: 'EOL' }, group, -1)
+      const group =
+        tree.down.at(-1) ?? treeAdd<Group>({id: id(), type: 'Group'}, tree, -1)
+      treeAdd<EOL>({id: id(), end, type: 'EOL'}, group, -1)
       continue
     }
 
@@ -115,12 +115,12 @@ export function TextTree(
           end: eol.end,
           expand: false,
           id: eol.id,
-          indent: prev ? (prev.indent + 1) : 0,
+          indent: prev ? prev.indent + 1 : 0,
           text: '',
-          type: 'Line',
+          type: 'Line'
         },
         prev ?? eol.up,
-        -1,
+        -1
       )
     }
 
@@ -129,11 +129,11 @@ export function TextTree(
       tree.down.at(-1)!.down.at(-1)?.type === 'EOL'
     ) {
       // No group or last line was EOL.
-      const group = treeAdd<Group>({ id: id(), type: 'Group' }, tree, -1)
+      const group = treeAdd<Group>({id: id(), type: 'Group'}, tree, -1)
       prev = treeAdd<Line>(
-        { end, expand: false, id: id(), indent: 0, text, type: 'Line' },
+        {end, expand: false, id: id(), indent: 0, text, type: 'Line'},
         group,
-        -1,
+        -1
       )
       continue
     }
@@ -152,13 +152,13 @@ export function TextTree(
         id: id(),
         indent: lineIndent,
         text,
-        type: 'Line',
+        type: 'Line'
       },
       // Indent matches a previous depth or previous depth was too deep?
       lineIndent <= prev!.indent
         ? prev!.up // Peer of line.
         : prev!, // Child of line.
-      -1,
+      -1
     )
   }
 
@@ -169,7 +169,7 @@ TextTree.addLine = (
   to: Line | Group,
   at: PositionLine,
   end: LineEnding,
-  id: IDFactory = factory,
+  id: IDFactory = factory
 ): TextTree => {
   let i
   let indent
@@ -187,9 +187,9 @@ TextTree.addLine = (
   }
 
   const line = treeAdd<Line>(
-    { end, expand: false, id: id(), indent, text: '', type: 'Line' },
+    {end, expand: false, id: id(), indent, text: '', type: 'Line'},
     up,
-    i,
+    i
   )
 
   return treeRoot(treeTouch(line))
@@ -199,10 +199,10 @@ TextTree.breakLine = (
   line: Line,
   at: number,
   end: LineEnding,
-  id: IDFactory = factory,
-): { root: TextTree; new: Line } => {
+  id: IDFactory = factory
+): {root: TextTree; new: Line} => {
   if (at < 0 || at > line.text.length) {
-    return { root: treeRoot(line), new: line }
+    return {root: treeRoot(line), new: line}
   }
   const lhs = line.text.slice(0, at)
   const rhs = line.text.slice(at)
@@ -217,18 +217,18 @@ TextTree.breakLine = (
       id: id(),
       indent: line.indent,
       text: rhs,
-      type: 'Line',
+      type: 'Line'
     },
     line.up,
-    line.up.down.indexOf(line) + 1,
+    line.up.down.indexOf(line) + 1
   )
-  return { root: treeRoot(next), new: next }
+  return {root: treeRoot(next), new: next}
 }
 
 TextTree.moveLine = (
   from: Line,
   to: Line | Group,
-  at: PositionLine,
+  at: PositionLine
 ): TextTree => {
   if (from === to) return treeRoot(from)
 
@@ -298,7 +298,7 @@ function measureIndent(str: string, indentW: IndentW): number {
 
 function nodesToString(
   nodes: readonly Readonly<TextTree | EOL | Group | Line>[],
-  indentW: IndentW,
+  indentW: IndentW
 ): string {
   let str = ''
   for (const node of nodes) {
@@ -307,14 +307,12 @@ function nodesToString(
     else if (node.type === 'Group') str += nodesToString(node.down, indentW)
     else if (node.type === 'Line') {
       const indent = (indentW === 'Tab' ? '\t' : ' '.repeat(indentW)).repeat(
-        node.indent,
+        node.indent
       )
-      str += `${indent}${node.text}${endToString(node.end)}${
-        nodesToString(
-          node.down,
-          indentW,
-        )
-      }`
+      str += `${indent}${node.text}${endToString(node.end)}${nodesToString(
+        node.down,
+        indentW
+      )}`
     } else node satisfies never
   }
   return str
@@ -326,8 +324,8 @@ function setIndent(line: Line, indent: number): void {
 }
 
 function* split(
-  str: string,
-): Generator<{ start: string; text: string; end: LineEnding | '' }> {
+  str: string
+): Generator<{start: string; text: string; end: LineEnding | ''}> {
   let start = ''
   let text = ''
   let end: LineEnding | '' = ''
@@ -338,17 +336,17 @@ function* split(
           end = 'CRLF'
           text = text.slice(0, -1)
         } else end = 'LF'
-        yield { start, text, end }
+        yield {start, text, end}
         start = text = end = ''
       } else text += char
     } else {
       if (char === ' ' || char === '\t') start += char
       else if (char === '\n') {
         end = 'LF'
-        yield { start, text, end }
+        yield {start, text, end}
         start = text = end = ''
       } else text += char
     }
   }
-  if (start || text || end) yield { start, text, end }
+  if (start || text || end) yield {start, text, end}
 }
diff --git a/src/tree/tree.test.ts b/src/tree/tree.test.ts
index a10a46c..a7fd37c 100644
--- a/src/tree/tree.test.ts
+++ b/src/tree/tree.test.ts
@@ -15,7 +15,6 @@ test('touch root', () => {
   // 4   5
   // |
   // 6
-  // deno-fmt-ignore
   const i: NumTree[] = [{n: 0}, {n: 1}, {n: 2}, {n: 3}, {n: 4}, {n: 5}, {n: 6}]
 
   i[0]!.down = [i[1]!, i[2]!, i[3]!]
@@ -55,7 +54,6 @@ test('touch mid', () => {
   // 4   5
   // |
   // 6
-  // deno-fmt-ignore
   const i: NumTree[] = [{n: 0}, {n: 1}, {n: 2}, {n: 3}, {n: 4}, {n: 5}, {n: 6}]
 
   i[0]!.down = [i[1]!, i[2]!, i[3]!]
@@ -96,7 +94,6 @@ test('touch leaf', () => {
   // 4   5
   // |
   // 6
-  // deno-fmt-ignore
   const i: NumTree[] = [{n: 0}, {n: 1}, {n: 2}, {n: 3}, {n: 4}, {n: 5}, {n: 6}]
 
   i[0]!.down = [i[1]!, i[2]!, i[3]!]
@@ -139,7 +136,6 @@ test('remove', () => {
   // 4   5
   // |
   // 6
-  // deno-fmt-ignore
   const i: NumTree[] = [{n: 0}, {n: 1}, {n: 2}, {n: 3}, {n: 4}, {n: 5}, {n: 6}]
 
   i[0]!.down = [i[1]!, i[2]!, i[3]!]
@@ -161,7 +157,6 @@ test('remove', () => {
   // 1 2 3
   //   |
   //   5
-  // deno-fmt-ignore
   const e: NumTree[] = [{n: 0}, {n: 1}, {n: 2}, {n: 3}, {n: 4}, {n: 5}, {n: 6}]
 
   e[0]!.down = [e[1]!, e[2]!, e[3]!]
@@ -186,7 +181,6 @@ test('add', () => {
   //   5 4
   //     |
   //     6
-  // deno-fmt-ignore
   const i: NumTree[] = [{n: 0}, {n: 1}, {n: 2}, {n: 3}, {n: 4}, {n: 5}, {n: 6}]
 
   i[0]!.down = [i[1]!, i[2]!, i[3]!]
@@ -208,7 +202,6 @@ test('add', () => {
   //   5 4
   //     |
   //     6
-  // deno-fmt-ignore
   const e: NumTree[] = [{n: 0}, {n: 1}, {n: 2}, {n: 3}, {n: 4}, {n: 5}, {n: 6}]
 
   e[0]!.down = [e[1]!, e[2]!, e[3]!]
diff --git a/src/tree/tree.ts b/src/tree/tree.ts
index d6007f9..aae4667 100644
--- a/src/tree/tree.ts
+++ b/src/tree/tree.ts
@@ -1,5 +1,5 @@
 /** n-ary tree. Subtypes may specify nonnullish linkage if treeAdd() is used. */
-export type Tree = { down?: undefined | Tree[]; up?: Tree | undefined }
+export type Tree = {down?: undefined | Tree[]; up?: Tree | undefined}
 /** Tree subtype with optional linkage. */
 export type OptTree<T> = Omit<T, 'down' | 'up'> & Tree
 
@@ -10,14 +10,14 @@ export type OptTree<T> = Omit<T, 'down' | 'up'> & Tree
 export function treeAdd<T extends Tree>(
   node: OptTree<T>,
   up: T['up'],
-  at: number,
+  at: number
 ): T {
   node.up = up
   node.down ??= [] // Allow nonnullish linkage.
-  if (!up) return <T> node
+  if (!up) return <T>node
   up.down ??= []
   up.down.splice(at < 0 ? up.down.length + 1 + at : at, 0, node)
-  return <T> node
+  return <T>node
 }
 
 /** Disconnect node from up. Return node. */
@@ -31,7 +31,7 @@ export function treeRemove<T extends Tree>(node: T): T {
 
 export function treeRoot<T extends Tree>(node: Tree): T {
   while (node.up) node = node.up
-  return <T> node
+  return <T>node
 }
 
 /**
@@ -41,12 +41,12 @@ export function treeRoot<T extends Tree>(node: Tree): T {
  * an immutable down tree would replace every up node.
  */
 export function treeTouch<T extends Tree>(node: Readonly<OptTree<T>>): T {
-  const touched = { ...node }
+  const touched = {...node}
   for (const down of node.down ?? []) down.up = touched
-  if (!node.up) return <T> touched
+  if (!node.up) return <T>touched
   const i = node.up.down?.indexOf(node) ?? -1
   if (i === -1) throw Error('up missing down tree')
   node.up.down![i] = touched
   treeTouch(node.up)
-  return <T> touched
+  return <T>touched
 }
diff --git a/src/uri-parser/uri-parser.ts b/src/uri-parser/uri-parser.ts
index 4543150..76e9514 100644
--- a/src/uri-parser/uri-parser.ts
+++ b/src/uri-parser/uri-parser.ts
@@ -1,4 +1,4 @@
-import type { DataURI } from './data-uri.js'
+import type {DataURI} from './data-uri.js'
 
 export function isDataURIStr(str: string): boolean {
   return str.startsWith('data:')
@@ -26,19 +26,19 @@ export function parseObjectURL(uri: string): string {
 }
 
 export function parseDataURIBlob(str: string): Blob | undefined {
-  const { data, encoding, mediaType } = parseDataURI(str) ?? {}
+  const {data, encoding, mediaType} = parseDataURI(str) ?? {}
   if (data == null) return
   if (encoding !== 'base64') return
   const encoder = new TextEncoder()
   const buffer = encoder.encode(data)
-  return new Blob([buffer], mediaType == null ? undefined : { type: mediaType })
+  return new Blob([buffer], mediaType == null ? undefined : {type: mediaType})
 }
 
 const dataURIRegex =
   /^(?<scheme>data):(?<mediaType>(?<mimeType>[^,;]+)(?<params>(;[^=,;]+=[^=,;]+)*))?(;(?<encoding>base64))?,(?<data>.*)$/i
 
 export function parseDataURI(str: string): DataURI | undefined {
-  const { groups } = dataURIRegex.exec(str) ?? {}
+  const {groups} = dataURIRegex.exec(str) ?? {}
   if (groups == null) return
   if (groups.scheme !== 'data') return
   if (groups.encoding != null && groups.encoding !== 'base64') return
@@ -50,9 +50,9 @@ export function parseDataURI(str: string): DataURI | undefined {
       groups.params
         ?.split(';')
         .slice(1) // Params start with `';'`. Skip the leading empty division.
-        .map((param) => param.split('=')) ?? [],
+        .map(param => param.split('=')) ?? []
     ),
     encoding: groups.encoding,
-    data: groups.data ?? '',
+    data: groups.data ?? ''
   }
 }
diff --git a/src/utils/bubble.ts b/src/utils/bubble.ts
index e9f9933..fc0fe14 100644
--- a/src/utils/bubble.ts
+++ b/src/utils/bubble.ts
@@ -1,4 +1,4 @@
 export function Bubble<T>(type: string, detail: T): CustomEvent<T> {
   // Composed bubbles through shadow DOM.
-  return new CustomEvent(type, { bubbles: true, composed: true, detail })
+  return new CustomEvent(type, {bubbles: true, composed: true, detail})
 }
diff --git a/src/utils/css-reset.ts b/src/utils/css-reset.ts
index 03ce9d1..5508f03 100644
--- a/src/utils/css-reset.ts
+++ b/src/utils/css-reset.ts
@@ -1,7 +1,9 @@
-import { css, type CSSResult } from 'lit'
+import {css, type CSSResult} from 'lit'
 
 export const cssReset: CSSResult = css`
-  *, *::after, *::before {
+  *,
+  *::after,
+  *::before {
     box-sizing: border-box; /* Dimensions include any border and padding. */
   }
 `
diff --git a/src/utils/element-util.ts b/src/utils/element-util.ts
index 3c040c5..a111768 100644
--- a/src/utils/element-util.ts
+++ b/src/utils/element-util.ts
@@ -14,7 +14,7 @@ export function composedAncestorElement(el: Element): Element | undefined {
 /** Composed Element.closest(). */
 export function composedClosest(
   selector: string,
-  el: Element,
+  el: Element
 ): Element | undefined {
   const closest = el.closest(selector)
   if (closest) return closest
@@ -31,7 +31,7 @@ export function composedClosestScrollable(el: Element): Element | undefined {
 
 /** Composed Document.elementFromPoint(). */
 export function composedElementFromPoint(x: number, y: number): Element | null {
-  for (let el = document.elementFromPoint(x, y);;) {
+  for (let el = document.elementFromPoint(x, y); ; ) {
     const next = el?.shadowRoot?.elementFromPoint(x, y)
     if (!next || el === next) return el
     el = next
@@ -41,9 +41,9 @@ export function composedElementFromPoint(x: number, y: number): Element | null {
 /** @arg xy Target in viewport client coordinates. */
 export function scrollTowardsEdge(
   el: Element,
-  xy: Readonly<{ x: number; y: number }>,
+  xy: Readonly<{x: number; y: number}>,
   threshold: number,
-  by: number,
+  by: number
 ): void {
   const sx = xy.x < threshold ? -1 : xy.x > el.clientWidth - threshold ? 1 : 0
   const sy = xy.y < threshold ? -1 : xy.y > el.clientHeight - threshold ? 1 : 0
diff --git a/src/utils/string-util.ts b/src/utils/string-util.ts
index 53a2394..3e51779 100644
--- a/src/utils/string-util.ts
+++ b/src/utils/string-util.ts
@@ -1,5 +1,5 @@
 /** Evaluate whether str is a finite number. */
 export function isNumeric(str: string): boolean {
   // https://stackoverflow.com/a/1830844/970346
-  return !isNaN(parseFloat(str)) && isFinite(<number> (<unknown> str))
+  return !isNaN(parseFloat(str)) && isFinite(<number>(<unknown>str))
 }