Function getFilesMapFromReasons

packages/next/src/utils.ts:939–991

(
  fileList: ReadonlySet<string>,
  reasons: NodeFileTraceReasons,
  ignoreFn?: (file: string, parent?: string) => boolean
)

}

export function getFilesMapFromReasons(
  fileList: ReadonlySet<string>,
  reasons: NodeFileTraceReasons,
  ignoreFn?: (file: string, parent?: string) => boolean
): ReadonlyMap<string, Set<string>> {
  // this uses the reasons tree to collect files specific to a
  // certain parent allowing us to not have to trace each parent
  // separately
  const parentFilesMap = new Map<string, Set<string>>();

  function propagateToParents(
    parents: Set<string>,
    file: string,
    seen = new Set<string>()
  ) {
    for (const parent of parents || []) {
      if (!seen.has(parent)) {
        seen.add(parent);
        let parentFiles = parentFilesMap.get(parent);

        if (!parentFiles) {
          parentFiles = new Set();
          parentFilesMap.set(parent, parentFiles);
        }

        if (!ignoreFn?.(file, parent)) {
          parentFiles.add(file);
        }
        const parentReason = reasons.get(parent);

        if (parentReason?.parents) {
          propagateToParents(parentReason.parents, file, seen);
        }
      }
    }
  }

  for (const file of fileList!) {
    const reason = reasons!.get(file);
    const isInitial =
      reason?.type.length === 1 && reason.type.includes('initial');

    if (
      !reason ||
      !reason.parents ||
      (isInitial && reason.parents.size === 0)
    ) {
      continue;
    }
    propagateToParents(reason.parents, file);
  }
  return parentFilesMap;
}

export const collectTracedFiles =
  (