rewrite function using ES6 syntax

index.js

@@ -1,22 +1,32 @@
-class NumberArray {
-  constructor(numbers) {
-    this.numbers = numbers;
-  }
+// class NumberArray {
+//   constructor(numbers) {
+//     this.numbers = numbers;
+//   }
 
-  getPositiveSum() {
-    let sum = 0;
-    for (let number of this.numbers) {
-      if (number > 0) {
-        sum += number;
-      }
-    }
-    return sum;
-  }
-}
+//   getPositiveSum() {
+//     let sum = 0;
+//     for (let number of this.numbers) {
+//       if (number > 0) {
+//         sum += number;
+//       }
+//     }
+//     return sum;
+//   }
+// }
 
-const numbers = [2, -4, 6, -8, 10, -12];
-const numberArray = new NumberArray(numbers);
-const positiveSum = numberArray.getPositiveSum();
+// const numbers = [2, -4, 6, -8, 10, -12];
+// const numberArray = new NumberArray(numbers);
+// const positiveSum = numberArray.getPositiveSum();
 
 // Input: [2, -4, 6, -8, 10, -12]
 // Output: 18
+
+const numbers = [2, -4, 6, -8, 10, -12];
+let getPositiveSum = numbers.reduce((sum, num) => {
+  if(num > 0) sum += num;
+  return sum;
+},0);
+
+console.log(getPositiveSum); 
+
+module.exports = {getPositiveSum};

index.test.js

@@ -0,0 +1,5 @@
+let {getPositiveSum} = require('./index');
+
+test('The output equal 18', ()=>{
+    expect(getPositiveSum).toBe(18);
+});