JavaScript: Get removed elements from the end of a given array until the passed function returns true
JavaScript fundamental (ES6 Syntax): Exercise-129 with Solution
Write a JavaScript program to get removed elements from the end of a given array until the passed function returns true.
- 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.
Sample Solution:
JavaScript Code:
//#Source https://bit.ly/2neWfJ2
const takeRightWhile = (arr, func) => {
for (let i of arr.reverse().keys())
if (func(arr[i])) return arr.reverse().slice(arr.length - i, arr.length);
return arr;
};
console.log(takeRightWhile([1, 2, 3, 4], n => n < 3));
Sample Output:
[3,4]
Flowchart:

Live Demo:
See the Pen javascript-basic-exercise-129-1 by w3resource (@w3resource) on CodePen.
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JavaScript: Tips of the Day
Chunks an array into n smaller arrays
Example:
const tips_chunkIntoN = (arr, n) => { const size = Math.ceil(arr.length / n); return Array.from({ length: n }, (v, i) => arr.slice(i * size, i * size + size) ); } console.log(tips_chunkIntoN([1, 2, 3, 4, 5, 6, 7,8], 4));
Output:
[[1,2],[3,4],[5,6],[7,8]]
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