Function editTaskAtIndex

packages/shared-domain/src/tasklists.ts:15–56

Internal: walk to the task line at `taskIndex`, hand its * TASK_LINE_RE match to `mutate`, and splice the result back in. * Returns the markdown unchanged if `mutate` returns null/the same * line, or the index is out of range.

(
  markdown: string,
  taskIndex: number,
  mutate: (match: RegExpMatchArray) => string | null
)

 *  Returns the markdown unchanged if `mutate` returns null/the same
 *  line, or the index is out of range. */
function editTaskAtIndex(
  markdown: string,
  taskIndex: number,
  mutate: (match: RegExpMatchArray) => string | null
): string {
  if (taskIndex < 0) return markdown

  const lines = markdown.split('\n')
  let currentTaskIndex = 0
  let inFence = false
  let fenceMarker: string | null = null

  for (let i = 0; i < lines.length; i++) {
    const line = lines[i]
    const fenceMatch = line.match(FENCE_RE)
    if (fenceMatch) {
      const marker = fenceMatch[2]
      if (!inFence) {
        inFence = true
        fenceMarker = marker
      } else if (marker === fenceMarker) {
        inFence = false
        fenceMarker = null
      }
      continue
    }
    if (inFence) continue

    const taskMatch = line.match(TASK_LINE_RE)
    if (!taskMatch) continue
    if (currentTaskIndex !== taskIndex) {
      currentTaskIndex += 1
      continue
    }

    const next = mutate(taskMatch)
    if (next == null || next === line) return markdown
    lines[i] = next
    return lines.join('\n')
  }
  return markdown
}

/** Line numbers (0-based) of every task line, indexed by task index. Counts
 *  exactly like `editTaskAtIndex` / `parseTasksFromBody` (fence-aware) so the