Fundamentals Final exam Practice sessions object sort

function solve(input) {
    let collection = {};
    for (let line of input) {
        if (line === 'END') {
            break;
        }
        let [command, road, racer, nextRoad] = line.split('->');
        if (command === 'Add') {
            if (!collection.hasOwnProperty(road)) {
                collection[road] = [];
            }
            collection[road].push(racer);
        } else if (command === 'Move') {

            let index = collection[road].indexOf(racer);
            if (index !== -1) {
                collection[road].splice(index, 1);
                collection[nextRoad].push(racer);
            }

        } else if (command === 'Close') {
            if (collection.hasOwnProperty(road)) {

                delete collection[road];
            }
        }

    }
    let sorted = Object.entries(collection);
    sorted = sorted.sort((a, b) => {
        return b[1].length - a[1].length || a[0].localeCompare(b[0]);
    });
    console.log("Practice sessions:");
    sorted.forEach(element => {

        console.log(element[0]);
        let racers = element[1];
        for (let name of racers) {
            console.log(`++${name}`);
        }

    });


}