deno/std/fs/utils.ts

import * as path from "../path/mod.ts";

/**
 * Test whether or not `dest` is a sub-directory of `src`
 * @param src src file path
 * @param dest dest file path
 * @param sep path separator
 */
export function isSubdir(
  src: string,
  dest: string,
  sep: string = path.sep
): boolean {
  if (src === dest) {
    return false;
  }
  const srcArray = src.split(sep);
  const destArray = dest.split(sep);
  // see: https://github.com/Microsoft/TypeScript/issues/30821
  return srcArray.reduce(
    // @ts-ignore
    (acc: true, current: string, i: number): boolean => {
      return acc && destArray[i] === current;
    },
    true
  );
}

export type PathType = "file" | "dir" | "symlink";

/**
 * Get a human readable file type string.
 *
 * @param fileInfo A FileInfo describes a file and is returned by `stat`,
 *                 `lstat`
 */
export function getFileInfoType(fileInfo: Deno.FileInfo): PathType | undefined {
  return fileInfo.isFile
    ? "file"
    : fileInfo.isDirectory
    ? "dir"
    : fileInfo.isSymlink
    ? "symlink"
    : undefined;
}