karma-runner/karma

[Question] Can you access preprocessor errors programatically?

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#2,064 opened on Apr 20, 2016

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 (9 comments) (1 reaction) (0 assignees)JavaScript (1,703 forks)batch import
help wantedtype: bug

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Description

I'm running karma programatically through the Server API and was wondering if there was a good way catch preprocessor errors when they occur.

Right now, if a preprocessor (babel for example) fails, I'll just see a message logged from Karma, but the server will still start up.

I'd like to be able to cancel the whole process, or at least catch the error when it occurs. I tried tracing my way through the source, and couldn't exactly understand what happens when a preprocessor invokes it's callback with an error: https://github.com/karma-runner/karma/blob/master/lib/preprocessor.js#L26

Any advice?

Contributor guide

Research direction
Examine the error handling in lib/preprocessor.js, specifically the callback invocation and how errors propagate. Look for ways to listen to error events or modify the server setup to capture preprocessor failures.
Tech stack
javascript
Domain
testing
Issue type
Research
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
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.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Mostly clear
Prerequisites
JavaScriptKarma
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60