Merge pull request #27 from SanjayBoricha/add-group-by-func

Added group_by function

Author: Hetarth02

index.js

@@ -486,43 +486,18 @@ function find_key_and_update(arr, parent_key, parent_value, target_key, target_v
 }
 
 /**
- * Group by key will group data by given key
- *
- * e.g i/p [
- *              {type: 'Movie', value: 'M1'},
- *              {type: 'TV show', value: 'TS1'},
- *              {type: 'Movie', value: 'M2'},
- *              {type: 'TV show', value: 'TS2'},
- *          ]
- * o/p
- *
- *          {
- *              Movie: [
- *                           {type: 'Movie', value: 'M1'},
- *                           {type: 'Movie', value: 'M1'},
- *                      ],
- *              'TV show': [
- *                            {type: 'TV show', value: 'TS1'},
- *                            {type: 'TV show', value: 'TS2'},
- *              ]
- *          }
- * @param {array of obejcts} input_arr
- * @param {string} key
+ * Group by key in array of object
+ * 
+ * @param array arr
+ * @param string key
+ * @returns object
  */
- function group_by_key(input_arr, key) {
-    let result = {};
-
-    result = input_arr.reduce((obj, item) => {
-        // if key already present in obj and push the new item
-        if (obj[item[key]]) {
-            obj[item[key]].push(item)
-        } else {
-            // if we don't find a key inside an obj, Then add key into object with value as an array
-            obj[item[key]] = [item]
-        }
-        return obj;
-    }, {})
-    return result;
+function group_by(arr, key) {
+    is_array(arr)
+    return arr.reduce(function (rv, x) {
+        (rv[x[key]] = rv[x[key]] || []).push(x);
+        return rv;
+    }, {});
 }
 
 export {
@@ -552,5 +527,5 @@ export {
     get_rms_value,
     find_key_and_update,
     find_and_update,
-    group_by_key,
+    group_by,
 };