Binary Search O(log n) JS

TheTechnoCult

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Sep 15, 2023

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function indexOfItem(arr, n) {
    let first = 0
    let last = arr.length - 1

    while (first <= last) {
        let mid = Math.floor(arr.length / 2)

        if (arr[mid] === n) {
            return mid
        } else if (arr[mid] < n) {
            first = mid + 1
        } else {
            last = mid - 1
        }
    }
    return null
}

// Note that this array is now sorted!
const names = ["Elida Sleight", "Francina Vigneault", "Lucie Hansman", "Nancie Rubalcaba"];

const index = indexOfItem(names, "Lucie Hansman");
console.log(index);