Function parseSubscriptionMarbles

packages/test/src/marble-parser.ts:154–224

(marbles?: string | null)

}

export function parseSubscriptionMarbles(marbles?: string | null): ParsedSubscription {
  if (marbles == null) {
    return {
      subscribedFrame: 0,
      unsubscribedFrame: Infinity,
    };
  }

  const characters = [...marbles];
  let frame = 0;
  let groupStart: number | undefined;
  let subscribedFrame = Infinity;
  let unsubscribedFrame = Infinity;

  for (let index = 0; index < characters.length; index++) {
    const character = characters[index];
    if (character === undefined) {
      break;
    }
    if (isWhitespace(character)) {
      continue;
    }

    const duration = readDuration(characters, index);
    if (duration) {
      frame += duration.milliseconds;
      index += duration.length - 1;
      continue;
    }

    switch (character) {
      case '-':
        frame += 1;
        break;
      case '(':
        if (groupStart !== undefined) {
          throw new Error('Nested subscription groups are not supported.');
        }
        groupStart = frame;
        frame += 1;
        break;
      case ')':
        if (groupStart === undefined) {
          throw new Error('Found a closing subscription group without an opening group.');
        }
        groupStart = undefined;
        frame += 1;
        break;
      case '^':
        if (subscribedFrame !== Infinity) {
          throw new Error('A subscription marble diagram can contain only one "^".');
        }
        subscribedFrame = groupStart ?? frame;
        frame += 1;
        break;
      case '!':
        if (unsubscribedFrame !== Infinity) {
          throw new Error('A subscription marble diagram can contain only one "!".');