Binary Search Using JavaScript

Last updated on 9 Dec, 2022

In Binary search, the data set to be searched for is halved every step.

Big O

Big O of binary search is O(log₂n) or just O(log N).

Implementing Binary Search using JavaScript

Here is the code:

function binarySearch(inputArray, searchTerm) {
  let low = 0;
  let high = inputArray.length;

  do {
    const mid = Math.floor(low + (high - low) / 2);
    const value = inputArray[mid];
    if (value === searchTerm) {
      return true;
    } else if (value > searchTerm) {
      high = mid;
    } else if (value < searchTerm) {
      low = mid + 1;
    }
  } while (low < high);

  return false;
}

We can call the function to test as shown below:

const inputArray = [2, 4, 8, 12, 56, 67, 89];
console.log(binarySearch(inputArray, 56)); // true
console.log(binarySearch(inputArray, 45)); // false

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Joby Joseph

Web Architect