Finding clusters of consecutive negative integers in JavaScript

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 negative numbers in the array.

Example

The code for this will be −

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

Output

The output in the console −

2