each

Transforms a list such that traversal of the list will result in the list item being transformed by the given (plan-time) callback. (If the result of this step is to be fed to another step directly, you must call applyTransforms() to force traversal of the list.)

Usage:

return each($oldList, ($listItem) => doSomethingWith($listItem));

Example generating a list of objects

Sometimes you have a step representing a collection of resources, $list, and you need to build a list of derivative objects from them. For example, the items in your collection might have x and y properties, and you might want to turn them into lng and lat attributes; which might look like this:

const $derivatives = each($list, ($item) =>
  object({
    name: $item.get("name"),
    lng: $item.get("x"),
    lat: $item.get("y"),
  }),
);
return $derivatives;

Remember: applyTransforms() if passing to another step

If you aren't returning the result of each() from a plan resolver, but are instead feeding it into another step, you will likely need to perform applyTransforms() to force the list transforms to take place before the dependent step receives the resulting values. Read more in applyTransforms().