Takes an array and groups the items together based on a given hasher function.This function is valid in v2.12.0 to v2.16.0. This function has been downloaded 9 times.
arr. If an array or a string it will be seen as the path within each item in
arrto the property by which to group each item.
hasherwill be arrays containing all of the corresponding items from
arr. If not specified the default is a new empty object.
opt_initialwith all of the keys specified by
hashercorresponding to arrays containing those values that come from
This function requires the following function which is included automatically: