Counting the clusters of positive numbers - JavaScript Arrays

Let’s say, we have an array of numbers like this −

const arr = [-1,-2,-1,0,-1,-2,-1,-2,-1,0,1,0];

We are required to write a JavaScript function that counts the consecutive groups of non-negative (positives and 0) numbers in the array.

Like here we have consecutive non-negatives from index 3 to 3 (only one element, but still a cluster) which forms one group and then from 9 to end of array forms the second group.

Therefore, for this array, the function should return 2.

Example

Following is the code −

const arr = [-1,-2,-1,0,-1,-2,-1,-2,-1,0,1,0];
const positiveClusters = arr => {
   return arr.reduce((acc, val, ind) => {
      if(val >= 0 && (arr[ind+1] < 0 || typeof arr[ind+1] === 'undefined')){
         acc++;
      };
      return acc;
   }, 0);
};
console.log(positiveClusters(arr));

Output

This will produce the following output in console −

2