code: function getErrorSource(error) {
    var match = /\n    at [^(]+ \((.*):(\d+):(\d+)\)/.exec(error.stack);
    if (match) {
      var source = match[1];
      var line = +match[2];
      var column = +match[3];
  
      // Support the inline sourceContents inside the source map
      var contents = fileContentsCache[source];
  
      // Support files on disk
      if (!contents && fs && fs.existsSync(source)) {
        try {
          contents = fs.readFileSync(source, 'utf8');
        } catch (er) {
          contents = '';
        }
      }
  
      // Format the line from the original source code like node does
      if (contents) {
        var code = contents.split(/(?:\r\n|\r|\n)/)[line - 1];
        if (code) {
          return source + ':' + line + '\n' + code + '\n' +
            new Array(column).join(' ') + '^';
        }
      }
    }
    return null;
  }
docs: Generate position and snippet of original source with pointer