Stringify JavaScript Objects -> JSON or other parsers safely

stringifySafely.ts

// Adapted from the Axios HTTP library
// https://github.com/axios/axios/blob/76f09afc03fbcf392d31ce88448246bcd4f91f8c/lib/defaults.js#L29

/**
 * Trim excess whitespace off the beginning and end of a string
 *
 * @param {String} str The String to trim
 * @returns {String} The String freed of excess whitespace
 */
const trim = (str) => {
  return str.trim ? str.trim() : str.replace(/^\s+|\s+$/g, '');
}

const stringifySafely = (rawValue: string | object, parser: Function, encoder: Function): string => {
  // If it's already stringified JSON, convert it back into an object first
  // Using JSON.parse by default, or a specified parser
  if (utils.isString(rawValue)) {
    try {
      (parser || JSON.parse)(rawValue);
      // Return the value with any spaces trimmed
      return trim(rawValue);
    } catch (e) {
      // Throw any error, apart from the stringifySafely
      if (e.name !== 'SyntaxError') {
        throw e;
      }
    }
  }

  // If it's already an object, stringify it
  // Using JSON.stringify by default, or a specified encoder
  return (encoder || JSON.stringify)(rawValue);
}