'Hash' safe property name. Take an object and represent it as a 'safe' javascript property string, for purposes of memoization.

hashSafePropertyName.js

    /**
     * @param  {Object|string} input - The string or object to flatten into a hash key string
     * @returns {string} - a string representing the object as a unique string.
     * @example hashSafePropertyName({a:200,b:500,c:[300,200,'eggs']}); // 'a$200_b$500_c$__300_200_eggs__' 
    */
    function hashSafePropertyName(input) {
      var isString = _.isString(input);
      var isObject = _.isObject(input) && !_.isEmpty(input) && _.isArray(input);

      if (!isString && !isObject) { 
        return false;
      }

      return (isObject ? JSON.stringify(input) : input)
          .replace(/[\"|{|}]/g,'')
          .replace(/,/g,'_') 
          .replace(/:/g,'$')
          .replace(/[\[|\]]/g,'__');
    }