binarysearch.js

function binaryArray(arr) {
  const array = arr

  const find = (searchvalue) => {
    let middle = Math.floor(array.length / 2)
    let left = 0
    let right = array.length
    while (right >= left) {
      const value = array[middle]
      if (value === searchvalue) {
        return middle
      } else if (value > searchvalue) {
        right = middle - 1
      } else {
        left = middle + 1
      }
      middle = Math.floor((left + right) / 2)
    }
    return -1
  }

  const add = (addvalue) => {
    let middle = Math.floor(array.length / 2)
    let left = 0
    let right = array.length
    while (right >= left) {
      const value = array[middle]
      if (value === addvalue) {
        return false
      } else if (value > addvalue) {
        right = middle - 1
      } else {
        left = middle + 1
      }
      middle = Math.floor((left + right) / 2)
    }
    array.splice(middle + 1, 0, addvalue)
    return true
  }

  return {
    find,
    add,
    array: function() { return array }
  }
}

console.assert(true == false, "Fail check, this test should fail")
let BA = binaryArray([1,3,5,7,10])
console.log("Array before inserts: ", BA.array())
console.assert(BA.find(1) == 0, "Index 0 was wrong")
console.assert(BA.find(3) == 1, "Index 1 was wrong")
console.assert(BA.find(5) == 2, "Index 2 was wrong")
console.assert(BA.find(7) == 3, "Index 3 was wrong")
console.assert(BA.find(10) == 4,"Index 4 was wrong")

console.assert(BA.add(5) == false, "Inserted value that already existed")

// insert value 9
console.assert(BA.add(9) == true, "Failed to insert value 9")
console.assert(BA.find(9) == 4, "Inserted value 9 at wrong index")

// insert value 100
console.assert(BA.add(100) == true, "Failed to insert value 100")
console.assert(BA.find(100) == 6, "Inserted value 100 at wrong index")

// insert value -10
console.assert(BA.add(-10) == true, "Failed to insert value -10")
console.assert(BA.find(-10) == 0, "Inserted value -10 at wrong index")


console.log("Array after inserts: ", BA.array())