Finding the inclination of arrays in JavaScript

We are required to write a JavaScript function that takes in an array of numbers and returns true if it’s either strictly increasing or strictly decreasing, otherwise returns false.

In Mathematics, a strictly increasing function is that function in which the value to be plotted always increases. Similarly, a strictly decreasing function is that function in which the value to be plotted always decreases.

Therefore, let’s write the code for this function −

Example

The code for this will be −

const arr = [12, 45, 6, 4, 23, 23, 21, 1];
const arr2 = [12, 45, 67, 89, 123, 144, 2656, 5657];
const sameSlope = (a, b, c) => (b - a  0 && c - b > 0);
const increasingOrDecreasing = (arr = []) => {
   if(arr.length 
Output
The output in the console will be −
false
true