code: function $file(params, fn) {
      if (params == null) {
          return params;
      }
      let file, encoding;
      if (typeof params === 'string') {
          file = params;
      } else if (Array.isArray(params) && params.length === 2) {
          file = params[0];
          encoding = params[1];
      }
      if (
          typeof file === 'string' &&
          (encoding === undefined || typeof encoding === 'string')
      ) {
          file = fn.$path(file);
          const fs = require('fs');
          if (fs.existsSync(file) && fs.lstatSync(file).isFile()) {
              return fs.readFileSync(file, { encoding });
          }
      }
      throw new Error(
          '$file expects a string or an array with two string elements'
      );
  }
docs: Resolve the path and read the file with an optional encoding
  
  @param {string|[string, string]} params
  @returns {string|Buffer}