phonebook binary search js

phonebook-binary-search.js

// binary search by key
const binarySearch = (phonebook, searchName) => {
  if(phonebook.length === 0) {
    return 'Phonebook is empty!'
  }
 
  let left = 0
  let right = phonebook.length - 1

  while(left <= right) {
    let middlePersonIndex = Math.round((left + right) / 2)
    let middlePerson = phonebook[middlePersonIndex]
    
    if (middlePerson.name === searchName) {
      return middlePerson.number
    }

    if (searchName < middlePerson.name) {
      right = middlePersonIndex - 1
    }

    if (searchName > middlePerson.name) {
      left = middlePersonIndex + 1
    }
  }
  
  return 'Name not found!'
}

export default binarySearch