Function boundedRenderText

ui-tui/src/lib/text.ts:133–175

(
  text: string,
  labelPrefix: string,
  { maxChars, maxLines }: { maxChars: number; maxLines: number }
)

) => boundedRenderText(text, 'showing live tail', { maxChars, maxLines })

const boundedRenderText = (
  text: string,
  labelPrefix: string,
  { maxChars, maxLines }: { maxChars: number; maxLines: number }
) => {
  if (text.length <= maxChars && text.split('\n', maxLines + 1).length <= maxLines) {
    return text
  }

  let start = 0
  let idx = text.length

  for (let seen = 0; seen < maxLines && idx > 0; seen++) {
    idx = text.lastIndexOf('\n', idx - 1)
    start = idx < 0 ? 0 : idx + 1

    if (idx < 0) {
      break
    }
  }

  const lineStart = start
  start = Math.max(lineStart, text.length - maxChars)

  if (start > lineStart) {
    const nextBreak = text.indexOf('\n', start)

    if (nextBreak >= 0 && nextBreak < text.length - 1) {
      start = nextBreak + 1
    }
  }

  const tail = text.slice(start).trimStart()
  const omittedLines = countNewlines(text, start)
  const omittedChars = Math.max(0, text.length - tail.length)

  const label =
    omittedLines > 0
      ? `[${labelPrefix}; omitted ${fmtK(omittedLines)} lines / ${fmtK(omittedChars)} chars]\n`
      : `[${labelPrefix}; omitted ${fmtK(omittedChars)} chars]\n`

  return `${label}${tail}`
}

const countNewlines = (text: string, end: number) => {
  let count = 0