Returns the smallest positive integer (greater than 0) that does not occur in A

smallestpositive.js

// you can write to stdout for debugging purposes, e.g.
// console.log('this is a debug message');

function solution(A) {
    // write your code in JavaScript (Node.js 8.9.4)
    let sorted = A.filter(a => a >= 1).sort((a, b) => a - b);
    // console.log('sorted', sorted)
    
    let minor = 1;
    
    for (let i = 0; i < sorted.length; i++) {
        
        console.log('minor', minor, 'sorted:', sorted[i], minor < sorted[i]);
        if (minor < sorted[i]) {
            return minor;
        }
        
        minor = sorted[i] + 1;
    }
    
    console.log('final', minor)
    
    return minor;
}

/*
This is a demo task.

Write a function:

function solution(A);

that, given an array A of N integers, returns the smallest positive integer (greater than 0) that does not occur in A.

For example, given A = [1, 3, 6, 4, 1, 2], the function should return 5.

Given A = [1, 2, 3], the function should return 4.

Given A = [−1, −3], the function should return 1.

Write an efficient algorithm for the following assumptions:

N is an integer within the range [1..100,000];
each element of array A is an integer within the range [−1,000,000..1,000,000].
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*/