Concert

function y(params = []) {
    params = params.slice(0, params.indexOf('start of concert'));
    let bands = {};
    let playtime = {};
    let totalPlaytime = 0;

    for (const line of params) {
        let [command, bandName, value] = line.split('; ');

        switch (command) {
            case 'Add':
                let members = value.split(', ');
                if (!bands.hasOwnProperty(bandName)) {
                    bands[bandName] = [];
                    for (let i = 0; i < members.length; i++) {
                        if (!bands[bandName].includes(members[i])) {
                            bands[bandName].push(members[i])
                        }
                    }
                } else {
                    for (let index = 0; index < members.length; index++) {
                        if (!bands[bandName].includes(members[index])) {
                            bands[bandName].push(members[index])
                        }
                    }
                }
                break;

            default:
                let timeOnStage = +value;
                totalPlaytime += timeOnStage;
                if (!playtime.hasOwnProperty(bandName)) {
                    playtime[bandName] = 0;
                    playtime[bandName] += timeOnStage;
                }
                break;
        }

    }

    console.log(`Total time: ${totalPlaytime}`);

    let playtimeArr = Object
        .entries(playtime)
        .sort((a, b) => b[1] - a[1] || a[0].localeCompare(b[0]))
        .forEach(member => {
            console.log(`${member[0]} -> ${member[1]}`);
        });


    let bandMembers = Object
    .entries(bands)
    .sort((a, b) => b[0].length - a[0].length);

    let topBand = bandMembers[0]

    console.log(topBand.shift());

    topBand[0]
    .forEach(member => {
        console.log(`=> ${member}`);
    })
}
y([
    'Play; The Beatles; 2584',
    'Add; The Beatles; John Lennon, Paul McCartney, George Harrison, Ringo Starr',
    'Add; Eagles; Glenn Frey, Don Henley, Bernie Leadon, Randy Meisner',
    'Play; Eagles; 1869',
    'Add; The Rolling Stones; Brian Jones, Mick Jagger, Keith Richards',
    'Add; The Rolling Stones; Brian Jones, Mick Jagger, Keith Richards, Bill Wyman, Charlie Watts, Ian Stewart',
    'Play; The Rolling Stones; 4239',
    'start of concert',
    'The Rolling Stones'
])