const max_length = 10 * 60;
const tracks = [
    {file: "A", length: 120},
    {file: "B", length: 240},
    {file: "C", length: 120},
    {file: "D", length: 180}
];



function f(list, len) {
    let ways = [];
    for(let i = 0; i < tracks.length; i++) {
        if(!~list.indexOf(i)) {
            let nextlen = len + tracks[i].length;
            if(nextlen <= max_length) {
                ways = ways.concat((f(list.concat([i]), nextlen)));
            }
        }
    }
    ways = ways.concat([[len, list]]);
    return ways;
}
var ways = f([], 0);
console.log(ways.sort(function(a, b) {
    return a[0] - b[0];
}));