Function compressNodeLocation

packages/core/src/hydration/compression.ts:30–47

(referenceNode: string, path: NodeNavigationStep[])

 * 'nextSibling'], the function returns: `bf2n`.
 */
export function compressNodeLocation(referenceNode: string, path: NodeNavigationStep[]): string {
  const result: Array<string | number> = [referenceNode];
  for (const segment of path) {
    const lastIdx = result.length - 1;
    if (lastIdx > 0 && result[lastIdx - 1] === segment) {
      // An empty string in a count slot represents 1 occurrence of an instruction.
      const value = (result[lastIdx] || 1) as number;
      result[lastIdx] = value + 1;
    } else {
      // Adding a new segment to the path.
      // Using an empty string in a counter field to avoid encoding `1`s
      // into the path, since they are implicit (e.g. `f1n1` vs `fn`), so
      // it's enough to have a single char in this case.
      result.push(segment, '');
    }
  }
  return result.join('');
}

/**
 * Helper function that reverts the `compressNodeLocation` and transforms a given