_.invertBy(object, [iteratee=_.identity])
varobject= { 'a': 1, 'b': 2, 'c': 1 }; _.invertBy(object); // => { '1': ['a', 'c'], '2': ['b'] }_.invertBy(object, function(value) { return'group'+value; }); // => { 'group1': ['a', 'c'], 'group2': ['b'] }
