Deprecate Iterator.helper in Storefront JS

INFO

This document represents an architecture decision record (ADR) and has been mirrored from the ADR section in our Shopware 6 repository. You can find the original version here

Context

The Storefront JavaScript currently offers a helper class src/helper/iterator.helper.js that can iterate over different objects like Maps, FormData, plain arrays etc. Using this approach has several downsides we want to address.

• It creates an unnecessary abstraction over the native alternative. Very often the Iterator.iterate() directly uses js plain forEach loop without any additional logic. Using the abstraction is actually creating more complexity.
• It prevents the developer from using the appropriate loop for the given data type and instead passes it to an iterator that does it with arbitrary data types.
• The iterator is a special shopware syntax that needs to be understood and documented. It is way easier to use web standards that everyone knows and that is also officially documented already.
• The usage throughout the codebase is inconsistent and the iterator helper is used alongside the native loops which can create confusion.
• It creates the impression that the data that is being iterated is some special custom object that needs a special iterator helper. In reality, it is a simple NodeList in 90% of the time.
• It creates an additional dependency/import in every file that is using it.

Decision

For all the above reasons we have decided to deprecate src/helper/iterator.helper.js, stop using it, and use native alternatives instead. We want to have a more lean and simple Storefront JavaScript that needs less special things to learn and understand.

Consequences

• The src/helper/iterator.helper.js is deprecated for v6.8.0.
• The usages of Iterator.iterate() are replaced with native alternatives.
• See 2025-01-28-use-native-iteration-instead-of-iterator-helper.md for the changelog and upgrade documentation.