Quick answer
On src, you can always specify files to ignore using “!”.
Example (you want to exclude all *.min.js files on your js folder and subfolder:
gulp.src(['js/**/*.js', '!js/**/*.min.js'])
You can do it as well for individual files.
Expanded answer:
Extracted from gulp documentation:
gulp.src(globs[, options])
Emits files matching provided glob or an array of globs. Returns a stream of Vinyl files that can be piped to plugins.
glob refers to node-glob syntax or it can be a direct file path.
So, looking to node-glob documentation we can see that it uses the minimatch library to do its matching.
On minimatch documentation, they point out the following:
if the pattern starts with a ! character, then it is negated.
And that is why using ! symbol will exclude files / directories from a gulp task