pastebin

function search(arr, x)

    let i = 0;

    let j = arr.length;

    while (i !== j)

    {

        let m = Math.floor((i + j) / 2);

        if (x === arr[m])

            return m;

        if (x < arr[m])

            j = m;

        else

            i = m + 1;

    }

    return null;

 

 

let items = [ 2, 3, 5, 7, 11, 13, 17 ];

 

console.log(search(items, 1));

console.log(search(items, 7));

console.log(search(items, 19));

 

 

let i = 0;

items = Array

  .apply(null, Array(10000))

  .map(() => ++i );

let count = 10000;

 

let start = new Date();

 

for (i = 0; i < count; i++)

  search(items, 7777);

 

let milliseconds = (new Date()) - start;

 

console.log(milliseconds * 100);