diff --git a/README.md b/README.md
index 3f87344cf..61243a0ce 100644
--- a/README.md
+++ b/README.md
@@ -113,8 +113,7 @@ var curry = f =>
 Use `filter()` to remove values that are part of `values`, determined using `includes()`.
 
 ```js
-var difference = (arr, values) =>
-  arr.filter(v => !values.includes(v));
+var difference = (arr, values) => arr.filter(v => !values.includes(v));
 ```
 
 ### Distance between two points
@@ -327,8 +326,7 @@ var scrollToTop = _ => {
 Use `filter()` to remove values that are not part of `values`, determined using `includes()`.
 
 ```js
-var difference = (arr, values) =>
-  arr.filter(v => values.includes(v));
+var difference = (arr, values) => arr.filter(v => values.includes(v));
 ```
 
 ### Sort characters in string (alphabetical)
@@ -367,7 +365,6 @@ var tail = arr => arr.slice(1);
 
 ### Unique values of array
 
-
 Use ES6 `Set` and the `...rest` operator to discard all duplicated values.
 
 ```js
diff --git a/snippets/difference-between-arrays.md b/snippets/difference-between-arrays.md
index 01e6c5883..51e805966 100644
--- a/snippets/difference-between-arrays.md
+++ b/snippets/difference-between-arrays.md
@@ -1,8 +1,7 @@
 ### Difference between arrays
 
-Use `filter()` to remove values that are part of `values`, determined using `indexOf()`.
+Use `filter()` to remove values that are part of `values`, determined using `includes()`.
 
 ```js
-var difference = (arr, values) =>
-  arr.filter(v => values.indexOf(v) === -1);
+var difference = (arr, values) => arr.filter(v => !values.includes(v));
 ```
diff --git a/snippets/similarity-between-arrays.md b/snippets/similarity-between-arrays.md
index b4d08de0a..4ba95bf04 100644
--- a/snippets/similarity-between-arrays.md
+++ b/snippets/similarity-between-arrays.md
@@ -1,8 +1,7 @@
 ### Similarity between arrays
 
-Use `filter()` to remove values that are not part of `values`, determined using `indexOf()`.
+Use `filter()` to remove values that are not part of `values`, determined using `includes()`.
 
 ```js
-var difference = (arr, values) =>
-  arr.filter(v => values.indexOf(v) !== -1);
+var difference = (arr, values) => arr.filter(v => values.includes(v));
 ```