How can I use the reduce function in advanced ways?

How can I use the reduce function in advanced ways?

The reduce function is powerful for aggregating data. What specific use case do you have in mind?

I want to flatten an array of arrays into a single array.

You can achieve that by using reduce like this: array.reduce((acc, val) => acc.concat(val), []). This will flatten the array.

Can I use reduce to count occurrences of items in an array?

Absolutely! You can use reduce to create an object that counts occurrences. For example: array.reduce((acc, item) => { acc[item] = (acc[item] || 0) + 1; return acc; }, {});.

What about using reduce with asynchronous operations?

For asynchronous operations, you might want to use async/await with reduce. You can map your array to promises and then reduce them.