function generateFakeData(n) {

  const result = [];

  const genders = ['female', 'male'];

  const age = ['18to33', '34to48', '49to64', 'other'];

  const day = ['monday', 'tuesday', 'wednesday', 'thursday', 'friday', 'saturday', 'sunday'];

  for (let i=0; i<n; i++) {

    result.push({

      gender: genders[Math.floor(Math.random() * genders.length)],

      age: age[Math.floor(Math.random() * age.length)],

      day: day[Math.floor(Math.random() * day.length)]

    });

  }

  return result;

}

​

console.log(generateFakeData(30));