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JavaScript: Get the highest index at which value should be inserted into array in order to maintain its sort order

JavaScript fundamental (ES6 Syntax): Exercise-141 with Solution

Write a JavaScript program to get the highest index at which value should be inserted into array in order to maintain its sort order.

  • Loosely check if the array is sorted in descending order.
  • Use Array.prototype.reverse() and Array.prototype.findIndex() to find the appropriate last index where the element should be inserted.

Sample Solution:

JavaScript Code:

//#Source https://bit.ly/2neWfJ2 
const sortedLastIndex = (arr, n) => {
  const isDescending = arr[0] > arr[arr.length - 1];
  const index = arr.reverse().findIndex(el => (isDescending ? n <= el : n >= el));
  return index === -1 ? 0 : arr.length - index;
};

console.log(sortedLastIndex([10, 20, 30, 30, 40], 30));

Sample Output:

4

Flowchart:

flowchart: Get the highest index at which value should be inserted into array in order to maintain its sort order

Live Demo:

See the Pen javascript-basic-exercise-141-1 by w3resource (@w3resource) on CodePen.


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Next: Write a JavaScript program to get the lowest index at which value should be inserted into array in order to maintain its sort order.

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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]]