Flattening

Flattening streams

Flattening arrays

You may have heard of a flatten function.

flatten functions take an input of some sort and “unwrap” it. (In this case, unwrapping an array is to pull out the elements in the array and use those.)

This hypothetical code snippet returns [2, 4, 7, 12]:

flatten([[2], [4, 7], 12])

Usually, a single call to flatten only unwraps by one layer.

Flattening promises and observables

Flatten iterates through the array, unwrapping ...