Differences

This shows you the differences between two versions of the page.

--- java-script:reduce:group-people-by-age [2023/08/07 20:35] – odefta
+++ java-script:reduce:group-people-by-age [2023/08/07 20:42] (current) – odefta
@@ Line 1: / Line 1: @@
 ====== Using reduce to group people by age ======
-;;;**reduce** is a method that applies a function against an accumulator and each element in the array (from left to right) to reduce it to a single value.;;; \\ \\
 In this example, the accumulator starts as an empty object {}, and the function is applied to each person object in the people array.
+This function is a neat example of how you can use **reduce** in conjunction with other modern JavaScript features like **destructuring** and the **nullish coalescing operator** to concisely perform a complex transformation on an array.
 <code javascript group-people-by-age-reduce.js>
@@ Line 11: / Line 11: @@
         let groupedPeopleByAge = people.reduce((group, person) => {
-            const { age } = person;
+            const { age } = person; //destructuring
-            group[age] = group[age] ?? [];
+            group[age] = group[age] ?? []; //nullish coalescing operatorn
             group[age].push(person.name);
             return group;