Binary Gap

LeetCode題目: 868. Binary Gap

My solution:

/**
 * @param {number} n
 * @return {number}
 */
let binaryGap = n => {
    let max = 0, indexArray = [];
    const binary = n.toString(2);
    for(let i=0; i<binary.length; i++) {
        if(binary[i] === '1') {
            if(indexArray.length) max =  Math.max(max, Number(i) - Number(indexArray.slice(-1)));
            indexArray.push(i);
        }
    }
    return max;    
};