Jekyll clear build folder with Gulp - gulp

Question

I'm using a build environment with Jekyll + Gulp. So, using the gulpfile.js below, the build process generate first a dist/css folder with the compiled css inside, and then clear the entire dist folder for put the jekyll build result inside. So, i'm not able to compile the scss files inside the dist folder because every time jekyll it completely clear it.
var gulp = require('gulp');
var browserSync = require('browser-sync');
var sass = require('gulp-sass');
var child = require('child_process');
gulp.task('jekyll', function (done) {
return child.spawn('jekyll' , ['build']).on('close', done);
});
gulp.task('jekyll-rebuild', ['jekyll'], function () {
browserSync.reload();
});
gulp.task('browser-sync', ['sass', 'jekyll'], function() {
browserSync({
server: {
baseDir: 'dist'
}
});
});
gulp.task('sass', function () {
return gulp.src('src/_sass/theme.scss')
.pipe(sass({
includePaths: ['scss'],
onError: browserSync.notify
}))
.pipe(browserSync.reload({stream:true}))
.pipe(gulp.dest('dist/css'));
});
gulp.task('watch', function () {
gulp.watch('src/_sass/*.scss', ['sass']);
gulp.watch(['src/*.html', 'src/_layouts/*.html', 'src/_includes/*'], ['jekyll-rebuild']);
});
gulp.task('default', ['browser-sync', 'watch']);

Answer 1

I have to avoid running jekyll task in parallel with styles and scripts so I have used a runSequence.
gulp.task('build', () => {
runSequence('jekyll', ['styles', 'scripts']);
});
gulp.task('default', ['build', 'browser-sync', 'watch']);

Answer 2

In your Jekyll config you need to declare which folders you want to keep:
keep_files: [ css, build ]
When clobbering the site destination, keep the selected files. Useful for files that are not generated by jekyll; e.g. files or assets that are generated by your build tool. The paths are relative to the destination.
https://jekyllrb.com/docs/configuration/