diff --git a/snippets/averageBy.md b/snippets/averageBy.md
index da0995f29..e31117182 100644
--- a/snippets/averageBy.md
+++ b/snippets/averageBy.md
@@ -5,9 +5,11 @@ Returns the average of an array, after mapping each element to a value using the
 Use `Array.map()` to map each element to the value returned by `fn`, `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`, divide by the `length` of the array.
 
 ```js
-const averageBy = (arr, fn) => arr.map(fn).reduce((acc, val) => acc + val, 0) / arr.length;
+const averageBy = (arr, fn) =>
+  arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val) => acc + val, 0) / arr.length;
 ```
 
 ```js
 averageBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n); // 5
+averageBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n'); // 5
 ```
diff --git a/snippets/countBy.md b/snippets/countBy.md
new file mode 100644
index 000000000..8001aff25
--- /dev/null
+++ b/snippets/countBy.md
@@ -0,0 +1,19 @@
+### countBy
+
+Groups the elements of an array based on the given function and returns the count of elements in each group.
+
+Use `Array.map()` to map the values of an array to a function or property name.
+Use `Array.reduce()` to create an object, where the keys are produced from the mapped results.
+
+```js
+const countBy = (arr, fn) =>
+  arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val, i) => {
+    acc[val] = (acc[val] || 0) + 1;
+    return acc;
+  }, {});
+```
+
+```js
+countBy([6.1, 4.2, 6.3], Math.floor); // {4: 1, 6: 2}
+countBy(['one', 'two', 'three'], 'length'); // {3: 2, 5: 1}
+```
diff --git a/snippets/groupBy.md b/snippets/groupBy.md
index 5d7f5bc55..e23c5c996 100644
--- a/snippets/groupBy.md
+++ b/snippets/groupBy.md
@@ -6,8 +6,8 @@ Use `Array.map()` to map the values of an array to a function or property name.
 Use `Array.reduce()` to create an object, where the keys are produced from the mapped results.
 
 ```js
-const groupBy = (arr, func) =>
-  arr.map(typeof func === 'function' ? func : val => val[func]).reduce((acc, val, i) => {
+const groupBy = (arr, fn) =>
+  arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val, i) => {
     acc[val] = (acc[val] || []).concat(arr[i]);
     return acc;
   }, {});
diff --git a/snippets/maxBy.md b/snippets/maxBy.md
index 596a4bd3f..9186dd009 100644
--- a/snippets/maxBy.md
+++ b/snippets/maxBy.md
@@ -5,9 +5,11 @@ Returns the maximum value of an array, after mapping each element to a value usi
 Use `Array.map()` to map each element to the value returned by `fn`, `Math.max()` to get the maximum value.
 
 ```js
-const maxBy = (arr, fn) => Math.max(...arr.map(fn));
+const maxBy = (arr, fn) =>
+  Math.max(...arr.map(typeof fn === 'function' ? fn : val => val[fn]));
 ```
 
 ```js
 maxBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n); // 8
+maxBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }],'n'); // 8
 ```
diff --git a/snippets/minBy.md b/snippets/minBy.md
index a185c7fc7..9f735119c 100644
--- a/snippets/minBy.md
+++ b/snippets/minBy.md
@@ -5,9 +5,11 @@ Returns the minimum value of an array, after mapping each element to a value usi
 Use `Array.map()` to map each element to the value returned by `fn`, `Math.min()` to get the maximum value.
 
 ```js
-const minBy = (arr, fn) => Math.min(...arr.map(fn));
+const minBy = (arr, fn) =>
+  Math.min(...arr.map(typeof fn === 'function' ? fn : val => val[fn]));
 ```
 
 ```js
 minBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n); // 8
+minBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n'); // 8
 ```
diff --git a/snippets/sumBy.md b/snippets/sumBy.md
index febb9248f..6e5812cc3 100644
--- a/snippets/sumBy.md
+++ b/snippets/sumBy.md
@@ -5,9 +5,11 @@ Returns the sum of an array, after mapping each element to a value using the pro
 Use `Array.map()` to map each element to the value returned by `fn`, `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`.
 
 ```js
-const sumBy = (arr, fn) => arr.map(fn).reduce((acc, val) => acc + val, 0);
+const sumBy = (arr, fn) =>
+  arr.map(typeof fn === 'function' ? fn : val => val[fn]).reduce((acc, val) => acc + val, 0);
 ```
 
 ```js
 sumBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], o => o.n); // 20
+sumBy([{ n: 4 }, { n: 2 }, { n: 8 }, { n: 6 }], 'n'); // 20
 ```
diff --git a/tag_database b/tag_database
index 9becb5b1a..45bce9b45 100644
--- a/tag_database
+++ b/tag_database
@@ -18,6 +18,7 @@ collectInto:adapter,function,array
 compact:array
 compose:function
 copyToClipboard:browser,string,advanced
+countBy:array,object
 countOccurrences:array
 createElement:browser,utility
 createEventHub:browser,event,advanced
@@ -56,7 +57,7 @@ getScrollPosition:browser
 getStyle:browser,css
 getType:type
 getURLParameters:utility,browser,string,url
-groupBy:array
+groupBy:array,object
 hammingDistance:math
 hasClass:browser,css
 hasFlags:node