code: function normalizeWatchFilePath (filepath, baseDir) {
    const { isAbsolute, relative } = require('path')
    if (isAbsolute(filepath)) {
      return relative(baseDir, filepath)
    }
    return filepath
  }
docs: Normalize file path and always return relative path,
  
  @param {string} filepath user's path
  @param {string} baseDir source directory
  @returns {string}