Split array into buckets of size n

bucketize

var bucketize = (x: any[], nInBucket: number) => {
    var i = 0.0;
    var iX = _.map(x, (x) => { return { i: i++, x: x }; });
    var groupedItems = _.groupBy(iX, (ixGrp) => { return Math.floor(ixGrp.i / nInBucket); });
             
    return _.map(_.values(groupedItems), (group: any[]) => {
        return _.pluck(group, 'x');
    });
}