JavaScript Sorting Algorithm: Sorted Index

JavaScript Sorting Algorithm: Exercise-22 with Solution

Find Lowest Insert Index (Array)

Write a JavaScript program to find the lowest index at which a value should be inserted into an array to maintain its sorting order.

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

Sample Solution:

JavaScript Code:

const sortedIndex = (arr, n) => {
  const isDescending = arr[0] > arr[arr.length - 1];
  const index = arr.findIndex(el => (isDescending ? n >= el : n <= el));
  return index === -1 ? arr.length : index;
};
console.log(sortedIndex([5, 3, 2, 1], 4));
console.log(sortedIndex([30, 50], 40));

Sample Output:

1
1

Flowchart:

Live Demo:

See the Pen javascript-common-editor by w3resource (@w3resource) on CodePen.

For more Practice: Solve these Related Problems:

• Write a JavaScript function that finds the lowest index for inserting a value in a sorted array using a linear search.
• Write a JavaScript function that handles empty arrays by returning 0 as the insertion index.
• Write a JavaScript function that compares the element at each index with the target to determine the correct insertion point.
• Write a JavaScript function that simulates the insertion and returns the updated array order.

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