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20220330_Vote/Ewide.Web.Entry/wwwroot/lib/xe-utils/groupBy.js

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+var isEmpty = require('./isEmpty')
+var isObject = require('./isObject')
+var isFunction = require('./isFunction')
+var property = require('./property')
+var each = require('./each')
+
+function createiterateEmpty (iterate) {
+  return function () {
+    return isEmpty(iterate)
+  }
+}
+
+/**
+  * 集合分组,默认使用键值分组,如果有iterate则使用结果进行分组
+  *
+  * @param {Array} obj 对象
+  * @param {Function} iterate 回调/对象属性
+  * @param {Object} context 上下文
+  * @return {Object}
+  */
+function groupBy (obj, iterate, context) {
+  var groupKey
+  var result = {}
+  if (obj) {
+    if (iterate && isObject(iterate)) {
+      iterate = createiterateEmpty(iterate)
+    } else if (!isFunction(iterate)) {
+      iterate = property(iterate)
+    }
+    each(obj, function (val, key) {
+      groupKey = iterate ? iterate.call(context, val, key, obj) : val
+      if (result[groupKey]) {
+        result[groupKey].push(val)
+      } else {
+        result[groupKey] = [val]
+      }
+    })
+  }
+  return result
+}
+
+module.exports = groupBy