Is_Bad_Version.js

// You are a product manager and currently leading a team to develop a new product. Unfortunately, the latest version of your product fails the quality check. Since each version is developed based on the previous version, all the versions after a bad version are also bad.

// Suppose you have n versions [1, 2, ..., n] and you want to find out the first bad one, which causes all the following ones to be bad.

// You are given an API bool isBadVersion(version) which will return whether version is bad. Implement a function to find the first bad version. You should minimize the number of calls to the API.

var solution = function(isBadVersion) {
    return function (n) {
        if(n === 1){
            return 1
        }
        var firstBad = 0
        var min = 1
        var max = n
        while(min <= max){
            var mid = Math.round(min + (max-min) / 2)
            console.log(mid)
            if(isBadVersion(mid)){
                firstBad = mid
                max = mid - 1
            }
            else {
              min = mid + 1 
            }
        }
        return firstBad
    }
};