viarno reshenie the pianist - final exam

function solve(input) {
    // parse initial catalog
    // - determine number of initial pieces
    // - for the next n lines, parse input and store piece in catalog
    let catalog = {};
    let n = Number(input.shift());
    //console.log(n);
    for (let i = 0; i < n; i++) {
        let [name, composer, key] = input.shift().split("|");
        //console.log(name, composer, key);
        catalog[name] = {
            composer,
            key
        };
    }

    // parse commands
    // - for each line, until "Stop" is received
    // -- determine command
    // -- execute operation, using given parameters
    while (input[0] != "Stop") {
        let tokens = input.shift().split("|");
        let command = tokens[0];
        let name = tokens[1];
        if (command == "Add") {
            if (catalog[name] != undefined) {
                console.log(`${name} is already in the collection!`);
            } else {
                catalog[name] = {
                    composer: tokens[2],
                    key: tokens[3]
                };
                console.log(`${name} by ${tokens[2]} in ${tokens[3]} added to the collection!`);
            }
        } else if (command == "Remove") {
           // if (catalog.hasOwnProperty(name) == false) {
            if (catalog[name] == undefined) {
                console.log(`Invalid operation! ${name} does not exist in the collection.`);
            } else {
                delete catalog[name];
                console.log(`Successfully removed ${name}!`);
            }
        } else if (command == "ChangeKey") {
            if (catalog[name] == undefined) {
                console.log(`Invalid operation! ${name} does not exist in the collection.`);
            } else {
                catalog[name].key = tokens[2];
                console.log(`Changed the key of ${name} to ${tokens[2]}!`);
            }
        }
    }
    //console.log(catalog);

    // sort catalog
    // - convert object into array
    // - sort aaray based on lexicographical order of piece name and then composer name
    let sorted = Object.entries(catalog).sort((a, b) => {
        //console.log(a);
        //console.log(b);
        let nameA = a[0];
        let nameB = b[0];

        let composerA = a[1].composer;
        let composerB = b[1].composer;
        return nameA.localeCompare(nameB) || composerA.localeCompare(composerB);
    });
    // print result
    // - for each element of sorted result, print information
    for (let [name, piece] of sorted) {
        console.log(`${name} -> Composer: ${piece.composer}, Key: ${piece.key}`);
    }
    // Add
    // - parse parameters
    // - if piece exists, print error
    // - else add new piece to catalog

    // Remove
    // - parse parameters
    // - if piece DOES NOT exist, print error
    // - else, remove piece from catalog

    // ChangeKey
    // - parse parameters
    // - if piece DOES NOT exist, print error
    // else update piece key to given value

}

solve([
  '3',
  'Fur Elise|Beethoven|A Minor',
  'Moonlight Sonata|Beethoven|C# Minor',
  'Clair de Lune|Debussy|C# Minor',
  'Add|Sonata No.2|Chopin|B Minor',
  'Add|Hungarian Rhapsody No.2|Liszt|C# Minor',
  'Add|Fur Elise|Beethoven|C# Minor',
  'Remove|Clair de Lune',
  'ChangeKey|Moonlight Sonata|C# Major',
  'Stop'
]
);