Collection functions should accept objects

[aarong]

I often find myself turning my data objects ({a: 1, b: 2, ...}) into arrays so that I can .map or .forEach them. It would be great if these function could accept objects directly.

[rgabo]

for the record, see issue #26 as well (not exactly a duplicate but same resolution suggested). Would you expect map and forEach to iterate over the keys ('a', 'b', ...) or the values (1, 2, ...)?

[jacobrask]

Underscore.js gives the iterator the arguments element, index, list if the passed list is an Array, and value, key, list if it is an Object.

[brianmaissy]

This is a duplicate of #168 and should be closed.