A guide to Object.groupBy : An alternative to Array.reduce

JavaScript developers often use the Array.prototype.reduce method for grouping data into categories, but it can be cumbersome for simple tasks. Object.groupBy, a new utility available cross-browser by the end of 2024, simplifies this process with a more intuitive approach for grouping and sorting lists. Compared to the traditional reduce method, Object.groupBy offers better readability and ease of use, automatically categorizing data based on a specified key. While reduce remains valuable for complex transformations, Object.groupBy is more efficient for basic grouping tasks, although it lacks the flexibility to modify data during the grouping process. Map.groupBy provides another option, especially useful for mutable data. Performance tests show that Object.groupBy is generally faster than Map.groupBy and reduce, but the appropriate method depends on specific project requirements. Both Object.groupBy and Map.groupBy have achieved baseline browser support, but developers targeting older browsers may need polyfills.