[NT-858] Replace .filter { ... }.first with .find(where: { ... }) #1066
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Scollaco
reviewed
Feb 13, 2020
| @@ -212,7 +212,7 @@ public final class UpdateDraftViewModel: UpdateDraftViewModelType, UpdateDraftVi | |||
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| self.showRemoveAttachmentConfirmation = addedAttachments | |||
| .takePairWhen(self.attachmentTappedProperty.signal) | |||
| .map { attachments, id in attachments.filter { $0.id == id }.first } | |||
| .map { attachments, id in attachments.first { $0.id == id } } | |||
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I noticed that in some places we use .first(where: { .... }) and in others simply .first { ... }. Should we adopt only one to keep it consistent? I don't have strong feelings about it though.
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Yeah that's intentional, when using first in a guard statement the compiler isn't able to figure it out unless we add the where: argument and parentheses.
Scollaco
approved these changes
Feb 14, 2020
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📲 What
Replaces instances of
.filter { ... }.firstwithfirst(where: { ... }).🤔 Why
This is just a simple optimization to not do unnecessary work when picking the first item from collections. In the case of
filterthe entire collection is traversed and each element is evaluated against the condition whereas.first(where:)stops once it finds a match and returns that element.🛠 How
Replaced use of
filterwithfirst(where:)where it made sense.For example, there are some places where we do something like:
This could be replaced with:
I felt that the sacrifice in readability and no material performance gain here didn't justify making those sorts of changes.
👀 See
Swift's Sequence type.
✅ Acceptance criteria