Function parseKeyPart

packages/core/src/keybindings/parser.ts:27–174

* Parse a single key part (e.g., "ctrl+s" or just "a"). * * @param part - Single key/modifier combination (no spaces) * @returns ParsedKey or error

(
  part: string,
)

 * @returns ParsedKey or error
 */
function parseKeyPart(
  part: string,
): { ok: true; value: ParsedKey } | { ok: false; error: KeyParseError } {
  if (part.length === 0) {
    return {
      ok: false,
      error: { code: "EMPTY_SEQUENCE", detail: "empty key part" },
    };
  }

  // Split on "+" to get modifiers and key
  const pieces = part.split("+");
  if (pieces.length === 0) {
    return {
      ok: false,
      error: { code: "EMPTY_SEQUENCE", detail: "empty key part" },
    };
  }

  let shift = false;
  let ctrl = false;
  let alt = false;
  let meta = false;
  let keyName: string | undefined;
  const seenModifiers = new Set<"shift" | "ctrl" | "alt" | "meta">();

  // Process each piece - all but last should be modifiers, last is the key
  for (let i = 0; i < pieces.length; i++) {
    const piece = pieces[i];
    if (piece === undefined || piece.length === 0) {
      return {
        ok: false,
        error: { code: "INVALID_KEY", detail: `empty component in "${part}"` },
      };
    }

    const isLast = i === pieces.length - 1;
    const pieceLower = piece.toLowerCase();

    if (MODIFIER_NAMES.has(pieceLower)) {
      // It's a modifier
      let modifier: "shift" | "ctrl" | "alt" | "meta" | null = null;
      switch (pieceLower) {
        case "shift":
          modifier = "shift";
          shift = true;
          break;
        case "ctrl":
        case "control":
          modifier = "ctrl";
          ctrl = true;
          break;
        case "alt":
          modifier = "alt";
          alt = true;
          break;
        case "meta":
        case "cmd":