Painfully slow removal of trailing whitespace on save of large files

[ArekSredzki]

Problem description

If one tries to save a large file with atom, the save is performed asynchronously, and if it is configured to remove trailing whitespace, it will block the entire editor for a painfully long time.

Very often I will have a large JSON file open and out of the practice of good habit, I will regularly hit meta-s to save the file. I will then be forced to take a stroll as the entire renderer window will be blocked for what is often a minute or so.

Today I finally performed a profile of the issue and nailed down the cause.
Here is the result for the reload of a large file (~150,000 lines).

Suggested changes

Fix Regex

Execution

I'll take a look at this tonight.

[lee-dohm]

I ran into this also with my tabs-to-spaces package which can do similar large-scale replacements on save, see lee-dohm/tabs-to-spaces#16.

[ArekSredzki]

@lee-dohm I'll take that into account when I do a deep dive this evening, thanks for letting me know 👍

[maxbrunsfeld]

This has been fixed: atom/whitespace#140. The fix will ship in Atom 1.14.