File utility functions.

• toBufferEncoding (encoding) ccnverts encoding names to Node's buffer encoding names.
• detectEncoding (filePath) detects the encoding of some file contents.
• detectContentsEncoding (buffer) detects the encoding of some contents.
• ensureDirectoryOf (filePath) checks if a directory exists and, if not, creates it.
• writeFile (filePath, contents, encoding) writes a file. If the file directory doesn't exit, it is created.
• subDirs (fromDir): Promise<Dirent[] gets a list of subdirectories.
• subDirsNames (fromDir): Promise<string[]> gets a list of subdirectories' names.
• findDirs (fromDirs, excludedDirs): Promise<string[]> finds directories under a set of dirs.
• findSubDirs (ofDir, excludedDirs = []): Promise<string[]> finds sub-directories of a dir.
• copy (toDir, sourcePatterns, options): Promise<string[]> copies files to a destination directory.
• copyFiles (sourceFiles, toDir) {): string[] copies multiple files to a directory.
• copyFile (sourceFilePath, destDir): string copies a file to a directory.
• FileContentsLang represents a file language and the detected file variants.
• FileContents (name, encoding, contents, lastModified, lang): string represents a file with contents:
  • static read(fileName, declaredEncoding) creates FileContents from a file path.
  • static readOrNew(fileName, declaredEncoding) reads a file or instantiate a brand new SsgFile if it doesn't exist.
  • static getLang(filePath): SsgFileLang guesses a file language and its language file variants in the same directory.
  • static getContents(fileName, declaredEncoding) gets the text contents of a file, and how it is encoded.
  • write() writes the file contents according to its encoding.