sangria-graphql/sangria

[Feature Request] flatMap over DeferredValue

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#629 opened on May 3, 2021

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 (0 comments) (2 reactions) (0 assignees)Scala (1,961 stars) (219 forks)batch import
help wanted

Description

Having map accessible on a DeferredValue is already very useful but I'd like to also have flatMap available so I can return another DeferredValue based on the result of the later and return it's subsequent value. I think there would be some overlap with the Relation-based mechanics but I think adding flatMap would add more ergonomics to dealing with DeferredValues.

Contributor guide

Tech stack
scala
Domain
apibackend
Issue type
feature
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
stale
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
mostly clear
Prerequisites
ScalaSangria basicsMonads
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
55
Research direction
Start by examining the existing `map` method on `DeferredValue` in the sangria codebase (likely in the `DeferredValue.scala` file). Understand how `flatMap` should differ by returning another `DeferredValue`. Consider how this interacts with the `Relation` mechanism to avoid conflicts. No comments or PRs exist yet, so the implementation can be straightforward. Ensure to add tests following the project's testing patterns.