Large diffs on snapshots are not truncated

[kernelwhisperer]

Describe the bug

I'm using expect(result).toMatchSnapshot() on a large array resulting in a 45.000 line snapshot.

The issue is that it takes a very long time for the test runner to display the diff inside the terminal.

I was expecting the output to be truncated, using the default value of chaiConfig.truncateThreshold, but the full diff is printed instead.

I've also tried using chaiConfig: { showDiff: false } which seems to have no effect.

Reproduction

Is this really needed?

I've went searching through the issues, my hunch is that snapshot diffing works differently and it ignores chaiConfig.

System Info

WSL 2 Ubuntu - vitest 1.2.2

Used Package Manager

npm

Validations

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[sheremet-va]

Is this really needed?

Yes, it is!

chaiConfig is not used for snapshots and never was because snapshots is not a chai feature.

Snapshots should show only changed lines, we use jest's diff display. Unless your whole snapshot is different, you shouldn't see it in full.

[kernelwhisperer]

The whole snapshot is different, yes.

Perhaps this is a feature request then, rather than a bug, correct?

[sheremet-va]

I guess we can add an option to truncate diff patches somehow. It should be disabled by default though.

[willieho]

I guess we can add an option to truncate diff patches somehow. It should be disabled by default though.

I'd like to take a shot at this enhancement/feature. After tracing the codebase, I think we can add a configuration option in DiffOptions so that we could have a more general control over diff truncation, instead of being specific to Snapshot. Does it sound reasonable?