thoughtbot/Argo

Make decoding lazy

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#185 opened on Jul 31, 2015

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enhancementhelp wanted

Description

Now we have parse the whole JSON value into the JSON type, but then you have a lot of overhead when you have a lot of properties that you don't use. I tried this with a type DecodableValue that has a helper method to cast the data of the DecodableValue to the type that you want. DecodableValue replaces JSON and also saves a lot of looping and switches.

Contributor guide

Tech stack
swift
Domain
backend
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.
1-2 days
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
SwiftArgo libraryfunctional programming
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
25
Research direction
The issue proposes making JSON decoding lazy to avoid overhead from parsing unused properties. Currently, Argo parses the entire JSON value into its JSON type. The suggestion is to use a DecodableValue type with a cast helper method. Investigate the current JSON type and DecodableValue implementation in the Argo source (likely in Argo/Types/). Look for any existing discussions or PRs linked to this issue. Consider implementing a lazy wrapper that defers decoding until the value is accessed. This is a significant architectural change, so careful design is needed to maintain type safety.