perf(calendar): use async ICS parsing to avoid blocking event loop#4143
Merged
khassel merged 1 commit intoMagicMirrorOrg:developfrom May 6, 2026
Merged
Conversation
Replace synchronous ical.parseICS() with ical.async.parseICS(), which processes data in batches via setImmediate(). Prevents the Node.js event loop from freezing on large calendars (1000+ events) on low-end hardware. Ref MagicMirrorOrg#4103
khassel
approved these changes
May 6, 2026
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This switches the calendar fetcher from synchronous to asynchronous ICS parsing.
It does not necessarily make parsing faster overall, but it avoids long event-loop stalls with large calendar files (especially on slower devices and with multiple feeds).
So this does not fully solve #4103 on its own, but it clearly mitigates it.
It should also combine well with a future pre-filter approach discussed in the issue:
Together, that is likely the strongest path to fully address #4103.