Function undoModification

browse/src/cdp-inspector.ts:612–664

(page: Page, index?: number)

 * Undo a modification by index (or last if no index given).
 */
export async function undoModification(page: Page, index?: number): Promise<void> {
  const idx = index ?? modificationHistory.length - 1;
  if (idx < 0 || idx >= modificationHistory.length) {
    const evictedNote = modHistoryTotalPushed > MOD_HISTORY_CAP
      ? ` (most recent ${MOD_HISTORY_CAP} only — ${modHistoryTotalPushed - MOD_HISTORY_CAP} earlier entries evicted at the cap)`
      : '';
    throw new Error(
      `No modification at index ${idx}. History has ${modificationHistory.length} entries${evictedNote}.`,
    );
  }

  const mod = modificationHistory[idx];

  if (mod.method === 'setStyleTexts') {
    // Try to restore via CDP
    try {
      await modifyStyle(page, mod.selector, mod.property, mod.oldValue);
      // Remove the undo modification from history (it's a restore, not a new mod)
      modificationHistory.pop();
    } catch (err: any) {
      // Fall back to inline restore — CDP may have disconnected or stylesheet changed
      if (!err?.message?.includes('closed') && !err?.message?.includes('Target') && !err?.message?.includes('style') && !err?.message?.includes('not found') && !err?.message?.includes('Element')) throw err;
      await page.evaluate(
        ([sel, prop, val]) => {
          const el = document.querySelector(sel);
          if (!el) return;
          if (val) {
            (el as HTMLElement).style.setProperty(prop, val);
          } else {
            (el as HTMLElement).style.removeProperty(prop);
          }
        },
        [mod.selector, mod.property, mod.oldValue]
      );
    }
  } else {
    // Inline modification — restore or remove
    await page.evaluate(
      ([sel, prop, val]) => {
        const el = document.querySelector(sel);
        if (!el) return;
        if (val) {
          (el as HTMLElement).style.setProperty(prop, val);
        } else {
          (el as HTMLElement).style.removeProperty(prop);
        }
      },
      [mod.selector, mod.property, mod.oldValue]
    );
  }

  modificationHistory.splice(idx, 1);
}

/**
 * Get the full modification history.