jestjs/jest

[Feature]: Upstream jest-file-snapshot?

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#12734 opened on Apr 25, 2022

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:rocket: Feature RequestHelp WantedPinned

Description

🚀 Feature Proposal

https://www.npmjs.com/package/jest-file-snapshot

I tend to migrate my snapshots from inline to jest-file-snapshots in almost every project I write tests for (either once the snapshots become unreasonably sized for inline or there's too many).

Do others have feelings about whether this library might be worth thinking about migrating into Jest itself?

Motivation

It's not offensive for me to add:

import { toMatchFile } from 'jest-file-snapshot';
 
expect.extend({ toMatchFile });

Per each file to use the plugin/types, but it is friction. As is ensuring that the generated files do not trigger the watcher, if the matchers were upstreamed Jest can know to watchlist ignore them.

Example

N/A

Pitch

It's ~150 LOC, so probably not a big maintenance burden and does a good job of expanding the scope of how folks can use snapshots

/cc @satya164

Contributor guide

Tech stack
typescriptjavascriptnodejs
Domain
testing
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.
needs maintainer response
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
clear
Prerequisites
JavaScript testing experienceFamiliarity with Jest snapshot featureUnderstanding of Node.js package management
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
40
Research direction
Review the jest file snapshot package source code (around 150 LOC) to understand its API and dependencies. Look at Jest's existing snapshot matcher implementation in packages/jest snapshot/src/. Check the discussion comments for maintainer feedback and consensus. Propose an integration approach that adds the toMatchFile matcher to Jest core, ensuring it respects watch file ignore rules.