Very slow when used with prettier-atom

[severo]

After installing prettier-plugin-svelte, saving a .svelte file in Atom (with prettier-atom formatting on save) turns to be very slow.

I published explanations to replicate here: https://github.com/severo/atom_prettier_svelte

Note that calling prettier from the CLI is instantaneous.

[Fil]

I can confirm the issue on @severo's project — takes 15s to save the Large.svelte file. (Atom 1.40.1, prettier-atom 0.57.3, macOS 10.14.6).

[chrisbrown-io]

I've been having the same issue when using prettier-plugin-svelte with SublimeJsPrettier.

Narrowed it down to being an issue with the cursorOffset/--cursor-offset argument being passed to the prettier cli.

It doesn't currently look like there is a way to disable this within prettier-atom (looks like they're working on it), but this is definitely the cause of the issue.

I'm not sure if this is an issue with the plugin internally calculating the cursor-offset, or prettier itself - will look into if I get more time.

e.g

When taking a moderately large .svelte file (100 lines+), without --cursor-offset argument, processed in < 1s:

prettier Example.svelte --config .prettierrc --loglevel debug

Whereas if you add the --cursor-offset argument, it's taking anywhere from 10s upwards
(0 as cursor offset is used as an example here, would be populated with correct integer by your IDE automatically) :

prettier Example.svelte --config .prettierrc --loglevel debug --cursor-offset 0

[jamesbirtles]

Very strange, thanks for the investigation @chrisbrown-io

[antonbrams]

do we have any solution for this issue? For some reason the prettier-plugin-svelte in combination with prettier-atom works freaking slow. With plain .js prettier-atom performs good. How can i fix a minute freeze of a svelte file?