how to chek value is in minus or plus javascript code example

Example: plus minus js

function plusMinus(arr) {     let positives = 0, negatives = 0, zeros = 0;     const len = arr.length || 0;           if (len > 0 && len <= 100) {          arr.map((elem, key) => {               if (elem > 0) {                    positives++;               } else if (elem < 0) {                    negatives++;                } else {                    zeros++;               }                                 return elem;           });      }           console.log((positives / len) || 0);     console.log((negatives / len) || 0);     console.log((zeros / len) || 0);      }