As a completely new developer, my favorite JavaScript tools were .map() and for loops. But recently, I've been determined to understand more complex methods like .reduce.

Working through the Callbacks & Higher-order Functions challenges in CSX has been the perfect introduction to reduce, which was intimidating for me to get started with. But reduce is a powerful method and definitely worth the effort.

The first .reduce() method I was exposed to was via MDN
arr.reduce(callback(accumulator, currentValue[, index[, array]])[, initialValue])
The W3Schools definition was better, but not by much.

So what's the best way to get over this intimidation factor?

1) start small with basic examples

• Most newbies are familiar with using .reduce() to aggregate the elements in an array

const theOG = (array) => {
  return array.reduce((acc, el) => {
    return acc + el
  })
}

2) remove any confusing terminology-- accumulator? What callback?

• I played with simple reduce applications using just x and y.
• But it might make more sense for you to use total and current or total and item
• Doesn't this syntax look familiar?

return array.reduce((x, y) =>  x + y % 2)
return array.reduce((x, y) =>  x - y)

3) console.log a lot

• If you're not sure what reduce is doing, console.log and see how that matches with your expectation.

const reduces = (array) => {
return array.reduce((acc, num) => {
  console.log(acc, num)
  return acc + num
  })
}

4) add other arguments and console.log those

array.reduce((acc, num, index, array) => {
    console.log(num, index)

5) practice + repetition

• Challenge yourself to solve different problems using .reduce() instead of the more obvious loops or methods.
• Solve the same problems over and over until they become second nature
• For me, the CSX challenges did a great job of that, but you can also make up your own challenges

As with every topic, FreeCodeCamp has a straightforward article you can reference when stuck.

You can also view my reduce challenges here