00001 var baseAssignValue = require('./_baseAssignValue'), 00002 createAggregator = require('./_createAggregator'); 00003 00005 var objectProto = Object.prototype; 00006 00008 var hasOwnProperty = objectProto.hasOwnProperty; 00009 00032 var countBy = createAggregator(function(result, value, key) { 00033 if (hasOwnProperty.call(result, key)) { 00034 ++result[key]; 00035 } else { 00036 baseAssignValue(result, key, 1); 00037 } 00038 }); 00039 00040 module.exports = countBy;