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--- java-script:reduce:group-people-by-age [2023/08/07 17:34] – odefta
+++ java-script:reduce:group-people-by-age [2025/01/02 18:22] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
-====== Use reduce to group people by age ======
+====== Using reduce to group people by age ======
+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 7: / 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;