Function identifySequence

src/ink/termio/parser.ts:245–256

* Identify the type of escape sequence from its raw form.

(
  seq: string,
)

 * Identify the type of escape sequence from its raw form.
 */
function identifySequence(
  seq: string,
): 'csi' | 'osc' | 'esc' | 'ss3' | 'unknown' {
  if (seq.length < 2) return 'unknown'
  if (seq.charCodeAt(0) !== C0.ESC) return 'unknown'

  const second = seq.charCodeAt(1)
  if (second === 0x5b) return 'csi' // [
  if (second === 0x5d) return 'osc' // ]
  if (second === 0x4f) return 'ss3' // O
  return 'esc'
}

// =============================================================================
// Main Parser