Posted: July 9, 2025 | Last updated: July 10, 2025 Learn JavaScript's Array Reduce method in 100 seconds. Take many things and reduce them down to one thing.

The reduce method accepts two arguments: a reducer function for the array that is used as a callback, and an optional initialValue argument. The reducer function takes four arguments: accumulator ...

Javascript reduce method parameters The reduce method accepts two arguments: a reducer function for the array that is used as a callback, and an optional initialValue argument.