Rename js snippets

snippets/js/s/take-array-elements-from-end-while.md

@@ -0,0 +1,28 @@
+---
+title: Remove array elements from the end while condition is met
+type: snippet
+language: javascript
+tags: [array]
+cover: tranquil-desktop
+dateModified: 2020-11-29T12:04:53+02:00
+---
+
+Removes elements from the end of an array until the passed function returns `false`.
+Returns the removed elements.
+
+- Create a reversed copy of the array, using the spread operator (`...`) and `Array.prototype.reverse()`.
+- Loop through the reversed copy, using a `for...of` loop over `Array.prototype.entries()` until the returned value from the function is falsy.
+- Return the removed elements, using `Array.prototype.slice()`.
+- The callback function, `fn`, accepts a single argument which is the value of the element.
+
+```js
+const takeRightWhile = (arr, fn) => {
+  for (const [i, val] of [...arr].reverse().entries())
+    if (!fn(val)) return i === 0 ? [] : arr.slice(-i);
+  return arr;
+};
+```
+
+```js
+takeRightWhile([1, 2, 3, 4], n => n >= 3); // [3, 4]
+```