Check If an Array is Growing by the Same Margin in JavaScript

We are required to write a JavaScript function that takes in an array of numbers. Our function should return true if the difference between all adjacent elements is the same positive number, false otherwise.

Example

The code for this will be −

const arr = [4, 7, 10, 13, 16, 19, 22];
const growingMarginally = arr => {
   if(arr.length <= 1){
      return true;
   };
   const diff = arr[1] - arr[0];
   if(diff < 0){
      return false;
   }
   for(let i = 0; i < arr.length - 1; i++){
      if (arr[i+1] - arr[i] !== diff){
         return false;
      }
   }
   return true;
};
console.log(growingMarginally(arr));

Output

And the output in the console will be −

true