Seemingly out of the blue, the Gulp processing I had set up for this site started to have a race condition. I’d run my watch command, change some CSS, and the processing would sometimes leave behind some extra files that were meant to be cleaned up during the processing. Like the cleanup tasks happened before the files landed in the file system (or something… I never really got to the bottom of it).
Nevermind about the specifics of that bug. I figured I’d go about solving it by upgrading things to use Gulp 4.x instead of 3.x, and running things in the built-in gulp.series command, which I thought would help (it did).
Getting Gulp 4.x going was a heck of a journey for me, involving me giving up for a year, then reigniting the struggle and ultimately getting it fixed. My trouble was that Gulp 4 requires a CLI version of 2.x while Gulp 3, for whatever reason, used a 3.x version. Essentially I needed to downgrade versions, but after trying a billion things to do that, nothing seemed to work, like there was a ghost version of CLI 3.x on my machine.
I’m sure savvier command-line folks could have sussed this out faster than me, but it turns out running command -v gulp will reveal the file path of where Gulp is installed which revealed /usr/local/share/npm/bin/gulp for me, and deleting it manually from there before re-installing the lastest version worked in getting me back down to 2.x.
Now that I could use Gulp 4.x, I re-wrote my gulpfile.js into smaller functions, each fairly isolated in responsibility. Much of this is pretty unique to my setup on this site, so it’s not meant to be some boilerplate for generic usage. I’m just publishing because it certainly would have been helpful for me to reference as I was creating it.
Things my particular Gulpfile does
Runs a web server (Browsersync) for style injection and auto-refreshing
Runs a file watcher (native Gulp feature) for running the right tasks on the right files and doing the above things
CSS processing
Sass > Autoprefixer > Minify
Break stylesheet cache from the templates (e.g. Put style.css in the right place for a WordPress theme and clean up files only needed during processing
JavaScript processing
Babel > Concatenate > Minify
Break browser cache for the