Phase A: Extract duplicated functions

150b3a-virtual-piano/music-sheet.gts

@@ -12,28 +12,14 @@ import MusicIcon from '@cardstack/boxel-icons/music-2';
 import { eq } from '@cardstack/boxel-ui/helpers';
 import { htmlSafe } from '@ember/template';
 import { Genre, GENRE_EMOJI } from './genre';
+import { diffLabel, diffClass } from './utils/diff-helpers';
 
 /* ── Difficulty helpers (VP.net scale 1–10) ──────────────────────────────
    1        → SUPER EASY
    2, 3, 4  → EASY
    5, 6, 7  → INTERMEDIATE
    8, 9, 10 → EXPERT
    ───────────────────────────────────────────────────────────────────────── */
-function diffLabel(level: number | null | undefined): string {
-  if (!level) return 'UNKNOWN';
-  if (level === 1) return 'SUPER EASY';
-  if (level <= 4) return 'EASY';
-  if (level <= 7) return 'INTERMEDIATE';
-  return 'EXPERT';
-}
-
-function diffClass(level: number | null | undefined): string {
-  if (!level) return 'diff-unknown';
-  if (level === 1) return 'diff-super-easy';
-  if (level <= 4) return 'diff-easy';
-  if (level <= 7) return 'diff-intermediate';
-  return 'diff-expert';
-}
 
 export class MusicSheet extends CardDef {
   static displayName = 'Music Sheet';

150b3a-virtual-piano/utils/diff-helpers.gts

@@ -0,0 +1,15 @@
+export function diffLabel(level: number | null | undefined): string {
+  if (!level) return 'UNKNOWN';
+  if (level === 1) return 'SUPER EASY';
+  if (level <= 4) return 'EASY';
+  if (level <= 7) return 'INTERMEDIATE';
+  return 'EXPERT';
+}
+
+export function diffClass(level: number | null | undefined): string {
+  if (!level) return 'diff-unknown';
+  if (level === 1) return 'diff-super-easy';
+  if (level <= 4) return 'diff-easy';
+  if (level <= 7) return 'diff-intermediate';
+  return 'diff-expert';
+}

150b3a-virtual-piano/virtual-piano.gts

@@ -32,6 +32,7 @@ import {
 } from '@cardstack/runtime-common';
 import PianoIcon from '@cardstack/boxel-icons/piano';
 import type { Genre } from './genre';
+import { diffLabel, diffClass } from './utils/diff-helpers';
 
 /* @ts-expect-error import.meta is valid ESM */
 const here: string = import.meta.url;
@@ -173,21 +174,6 @@ interface SongData {
 }
 
 /* ── Difficulty helpers (mirrors piano-song.gts) ─────────────────────── */
-function diffLabel(level: number): string {
-  if (!level) return '';
-  if (level === 1) return 'SUPER EASY';
-  if (level <= 4) return 'EASY';
-  if (level <= 7) return 'INTERMEDIATE';
-  return 'EXPERT';
-}
-
-function diffClass(level: number): string {
-  if (!level) return 'diff-unknown';
-  if (level === 1) return 'diff-super-easy';
-  if (level <= 4) return 'diff-easy';
-  if (level <= 7) return 'diff-intermediate';
-  return 'diff-expert';
-}
 
 /* ── Piano key layout data ───────────────────────────────────────────── */
 interface KeyData {
@@ -757,7 +743,8 @@ class IsolatedVirtualPiano extends Component<typeof VirtualPiano> {
   }
 
   get difficultyLabel(): string {
-    return diffLabel(this.selectedSong?.difficulty ?? 0);
+    if (!this.selectedSong?.difficulty) return '';
+    return diffLabel(this.selectedSong.difficulty);
   }
 
   get difficultyClass(): string {

41e20f-wedding-table-seating-planner/commands/analyze-floor-plan-command.gts

@@ -2,15 +2,7 @@ import { CardDef, field, contains } from 'https://cardstack.com/base/card-api';
 import StringField from 'https://cardstack.com/base/string';
 import { Command } from '@cardstack/runtime-common';
 import SendRequestViaProxyCommand from '@cardstack/boxel-host/commands/send-request-via-proxy';
-
-function arrayBufferToBase64(buffer: ArrayBuffer): string {
-  let binary = '';
-  let bytes = new Uint8Array(buffer);
-  for (let i = 0; i < bytes.byteLength; i++) {
-    binary += String.fromCharCode(bytes[i]);
-  }
-  return btoa(binary);
-}
+import { arrayBufferToBase64 } from '../utils/encoding';
 
 async function toDataUrl(url: string): Promise<string> {
   if (url.startsWith('data:image/')) return url;

41e20f-wedding-table-seating-planner/components/tsp.gts

@@ -23,6 +23,7 @@ import {
   POSTER_ASPECTS,
 } from '../commands/invitation-poster-command';
 import { debounce } from 'lodash-es';
+import { arrayBufferToBase64 } from '../utils/encoding';
 import type { TableSeatingPlanner } from '../table-seating-planner';
 import { Guest } from '../guest';
 import { Host } from '../host';
@@ -10751,18 +10752,6 @@ function clampNum(v: unknown, min: number, max: number, def: number): number {
   if (!isFinite(n)) return def;
   return Math.max(min, Math.min(max, Math.round(n)));
 }
-function arrayBufferToBase64(buffer: ArrayBuffer): string {
-  let binary = '';
-  let bytes = new Uint8Array(buffer);
-  let chunk = 0x8000;
-  for (let i = 0; i < bytes.length; i += chunk) {
-    binary += String.fromCharCode.apply(
-      null,
-      Array.from(bytes.subarray(i, i + chunk)) as unknown as number[],
-    );
-  }
-  return btoa(binary);
-}
 function imageDims(src: string): Promise<{ w: number; h: number }> {
   return new Promise((resolve) => {
     let img = new Image();

41e20f-wedding-table-seating-planner/utils/encoding.gts

@@ -0,0 +1,15 @@
+export function arrayBufferToBase64(buffer: ArrayBuffer): string {
+  let binary = '';
+  let bytes = new Uint8Array(buffer);
+  // Chunk to avoid quadratic string concatenation and the call-stack/argument
+  // limit of String.fromCharCode.apply on large buffers (floor plan uploads
+  // allow up to 25MB).
+  let chunk = 0x8000;
+  for (let i = 0; i < bytes.length; i += chunk) {
+    binary += String.fromCharCode.apply(
+      null,
+      Array.from(bytes.subarray(i, i + chunk)) as unknown as number[],
+    );
+  }
+  return btoa(binary);
+}