minDistance.js

function minimumDistances(numbers) {
    const numberQuantity = numbers.length;
    const firstOccurrences = {};
    let minDistance = Infinity;
    
    for (let idx = 0; idx < numberQuantity; idx += 1) {
        const num = numbers[idx];
        const firstOccurrenceIdx = firstOccurrences[num];
        
        if (firstOccurrenceIdx === undefined) {
            firstOccurrences[num] = idx;
        } else if (idx - firstOccurrenceIdx < minDistance) {
            minDistance = idx - firstOccurrenceIdx;
        }
    }
  
    return minDistance !== Infinity ? minDistance : -1;
}