TypeError: Parameter "url" must be a string, not undefined

[shanmuga2414]

url.js:103
throw new TypeError('Parameter "url" must be a string, not ' + typeof url);
^

TypeError: Parameter "url" must be a string, not undefined
at Url.parse (url.js:103:11)
at Object.urlParse [as parse] (url.js:97:13)
at module.exports. (/home/wallace/development/bikeAppointment/node_modules/google-search-scraper/index.js:101:27)
at module.exports.exports.each (/home/wallace/development/bikeAppointment/node_modules/cheerio/lib/api/traversing.js:226:24)
at extractResults (/home/wallace/development/bikeAppointment/node_modules/google-search-scraper/index.js:95:21)
at onPage (/home/wallace/development/bikeAppointment/node_modules/google-search-scraper/index.js:32:26)
at Request._callback (/home/wallace/development/bikeAppointment/node_modules/google-search-scraper/index.js:86:9)
at Request.self.callback (/home/wallace/development/bikeAppointment/node_modules/google-search-scraper/node_modules/request/request.js:122:22)
at emitTwo (events.js:126:13)
at Request.emit (events.js:214:7)