The block "Deduplicate list" allows you to remove duplicates from a list (array) of objects). Objects will be compared based on one given key. If the values of the key are the same, all but one object will be removed from the output.
The input "key" accepts a key such as email or a nested key such as profile.email.
In the above example inputs and example list, the output of the block will be:
This block does not use an iterator, which means that the input list will be loaded in memory before doing the deduplication. This means that a Blend using this block will fail with an "out of memory" error for very large lists.