Enhancing JavaScript Programming Skills

Introduction

In this lab, we will delve into the world of JavaScript programming and work on enhancing our skills in the language. We will work on various exercises and projects that will help us understand the fundamentals of the language, including variables, data types, functions, and loops. By the end of this lab, we will have a solid foundation in JavaScript programming and be equipped to take on more complex programming challenges.

Skills Graph

Function to Find Insertion Index in Sorted Array

To find the lowest index to insert a value in an array and maintain its sorting order, use the function sortedIndexBy(arr, n, fn) in JavaScript.

This function loosely checks if the array is sorted in descending order and then uses Array.prototype.findIndex() to find the appropriate index based on the iterator function fn.

Here's the code for the sortedIndexBy() function:

const sortedIndexBy = (arr, n, fn) => {
  const isDescending = fn(arr[0]) > fn(arr[arr.length - 1]);
  const val = fn(n);
  const index = arr.findIndex((el) =>
    isDescending ? val >= fn(el) : val <= fn(el)
  );
  return index === -1 ? arr.length : index;
};

You can call the function with an array of objects, a value to insert, and an iterator function.

For example, sortedIndexBy([{ x: 4 }, { x: 5 }], { x: 4 }, o => o.x) returns 0, which is the index where the { x: 4 } object should be inserted to maintain the sorting order based on the x property.

Summary

Congratulations! You have completed the Insertion Index in Sorted Array Based on Function lab. You can practice more labs in LabEx to improve your skills.