Modified binary search to find the nearest value of an array based on the user input.

Compare and Conquer

var kVAStandard = [
  900, 1300, 2200, 3500, 4400, 5500, 6600, 7700, 11000, 12000, 13000, 14000, 15000, 16000, 17000, 18000, 19000, 20000, 30000, 50000, 75000, 100000
]

const conquer = (left, right, val)=>{
  console.log('conquer', left, right, val)
  if(left.length === 1 && right.length === 1){
    if(Math.abs(left[0] - val) > Math.abs(right[0] - val)){
      console.log('conquer return right', right[0])
      return [right[0]]
    }
    console.log('conquer return left', left[0])
    return [left[0]]
  }
  else{
    return conquer(compare(left, val), compare(right, val), val)
  }
}

const compare = (arr, val)=>{
  console.log('compare', arr, val)
  if(val <= arr[0]){
    console.log('compare return ' + [arr[0]])
    return [arr[0]]
  }
  else if(val >= arr[arr.length-1]){
    console.log('compare return ' + [arr[arr.length-1]])
    return [arr[arr.length-1]]
  }
  else{
    const middle = Math.ceil(arr.length / 2)
    const left = arr.slice(0, middle)
    const right = arr.slice(middle)
    return conquer(left, right, val)
  }
}

// Find the nearest value in an array with user input (2000)
const result = compare(kVAStandard, 2000)
// Output 2200
console.log(result[0])