how to split array into n groups? (factorize, or _.partition array) [duplicate]

Answer 1

There are multiple to do this:

I. Normal function

function partition(items, n) {
    var result = _.groupBy(items, function(item, i) {
        return Math.floor(i % n);
    });
    return _.values(result);
}

myArray = [1,2,3,4,5,6,7,8,9,10];
partition(myArray, 3);

II. Adding a prototype method

Array.prototype.partition = function(n) {
    var result = _.groupBy(this, function(item, i) {
        return Math.floor(i % n);
    });
    return _.values(result);
}

myArray = [1,2,3,4,5,6,7,8,9,10];
myArray.partition(3)

Create an _.partitionToGroups method

_.partitionToGroups = function(items, n) {
    var result = _.groupBy(items, function(item, i) {
        return Math.floor(i % n);
    });
    return _.values(result);
}

myArray = [1,2,3,4,5,6,7,8,9,10];
_.partitionToGroups(myArray, 3);