TypeError: Object.values is not a function

[olivermanumbas]

\node_modules\node-rake\index.js:63
Object.values(wordFreq).forEach((freq) => { wordDegree[freq] += wordFreq[freq]; });
^

TypeError: Object.values is not a function
at Rake.calculateKeywordScores (C:\Users\john.manumbas\Desktop\bots\Sample Node\node_modules\node-rake\index.js:63:12)
at Rake.generate (C:\Users\john.manumbas\Desktop\bots\Sample Node\node_modules\node-rake\index.js:88:29)
at Object.generate (C:\Users\john.manumbas\Desktop\bots\Sample Node\node_modules\node-rake\app.js:13:21)
at Object. (C:\Users\john.manumbas\Desktop\bots\Sample Node\SpeechAPI\node_rake_sample.js:4:23)
at Module._compile (module.js:570:32)
at Object.Module._extensions..js (module.js:579:10)
at Module.load (module.js:487:32)
at tryModuleLoad (module.js:446:12)
at Function.Module._load (module.js:438:3)
at Module.runMain (module.js:604:10)

Node Version: v6.10.3