Rename js snippets

snippets/js/s/array-is-sorted.md

@@ -0,0 +1,32 @@
+---
+title: Array is sorted
+type: snippet
+language: javascript
+tags: [array]
+cover: italian-horizon
+dateModified: 2020-10-20T23:02:01+03:00
+---
+
+Checks if a numeric array is sorted.
+
+- Calculate the ordering `direction` for the first pair of adjacent array elements.
+- Return `0` if the given array is empty, only has one element or the `direction` changes for any pair of adjacent array elements.
+- Use `Math.sign()` to covert the final value of `direction` to `-1` (descending order) or `1` (ascending order).
+
+```js
+const isSorted = arr => {
+  if (arr.length <= 1) return 0;
+  const direction = arr[1] - arr[0];
+  for (let i = 2; i < arr.length; i++) {
+    if ((arr[i] - arr[i - 1]) * direction < 0) return 0;
+  }
+  return Math.sign(direction);
+};
+```
+
+```js
+isSorted([0, 1, 2, 2]); // 1
+isSorted([4, 3, 2]); // -1
+isSorted([4, 3, 5]); // 0
+isSorted([4]); // 0
+```