gulp 4 not updating CSS and JS - wordpress

Question

I am developing my own themes for WordPress, I came to know about Glup and how easy it made my workflow, the problem I am facing with my below code is I am able to see the immediate changes I am making to the main page (html or php) but any changes I am making to the css files or the java-script files is not effected at all, still I have to manually refresh the page:
var gulp = require('gulp'),
settings = require('./settings'),
webpack = require('webpack'),
browserSync = require('browser-sync').create(),
postcss = require('gulp-postcss'),
rgba = require('postcss-hexrgba'),
autoprefixer = require('autoprefixer'),
cssvars = require('postcss-simple-vars'),
nested = require('postcss-nested'),
cssImport = require('postcss-import'),
mixins = require('postcss-mixins'),
colorFunctions = require('postcss-color-function');
gulp.task('styles', function() {
return gulp.src(settings.themeLocation + 'css/style.css')
.pipe(postcss([cssImport, mixins, cssvars, nested, rgba, colorFunctions, autoprefixer]))
.on('error', (error) => console.log(error.toString()))
.pipe(gulp.dest(settings.themeLocation));
});
gulp.task('scripts', function(callback) {
webpack(require('./webpack.config.js'), function(err, stats) {
if (err) {
console.log(err.toString());
}
console.log(stats.toString());
callback();
});
});
gulp.task('watch', function() {
browserSync.init({
notify: false,
proxy: settings.urlToPreview,
ghostMode: false
});
gulp.watch('./**/*.php', function(done) {
browserSync.reload();
done();
});
gulp.watch(settings.themeLocation + 'css/**/*.css', gulp.parallel('waitForStyles'));
gulp.watch([settings.themeLocation + 'js/modules/*.js', settings.themeLocation + 'js/scripts.js'], gulp.parallel('waitForScripts'));
});
gulp.task('waitForStyles', gulp.series('styles', function() {
return gulp.src(settings.themeLocation + 'style.css')
.pipe(browserSync.stream());
}))
gulp.task('waitForScripts', gulp.series('scripts', function(cb) {
browserSync.reload();
cb()
}))

Answer 1

Try this:
gulp.task('styles', function() {
return gulp.src(settings.themeLocation + 'css/style.css')
.pipe(postcss([cssImport, mixins, cssvars, nested, rgba, colorFunctions, autoprefixer]))
.on('error', (error) => console.log(error.toString()))
.pipe(gulp.dest(settings.themeLocation))
// added below
.pipe(browserSync.stream());
});
// now this task is unnecessary:
// gulp.task('waitForStyles', gulp.series('styles', function() {
// return gulp.src(settings.themeLocation + 'style.css')
// .pipe(browserSync.stream());
// }))
// cb added, called below
gulp.task('watch', function(cb) {
browserSync.init({
notify: false,
proxy: settings.urlToPreview,
ghostMode: false
});
gulp.watch('./**/*.php', function(done) {
browserSync.reload();
done();
});
// change to gulp.series below
// gulp.watch(settings.themeLocation + 'css/**/*.css', gulp.series('waitForStyles'));
// changed to 'styles' below
gulp.watch(settings.themeLocation + 'css/**/*.css', gulp.series('styles'));
gulp.watch([settings.themeLocation + 'js/modules/*.js', settings.themeLocation + 'js/scripts.js'], gulp.series('waitForScripts'));
cb();
});
I have seen gulp4 have trouble with just a single task ala gulp.parallel('oneTaskHere'), so try swapping parallel with series in your watch statements as above code.
I made some edits to simplify the code - give it a try. No need for 'waitForStyles', just move the browserSync.stream() pipe to the end of the styles task.
Or instead of moving the browserSync.stream pipe, just do this:
gulp.watch(settings.themeLocation + 'css/**/*.css', gulp.series('styles', browserSync.reload));
but I seem to have better luck with the browserSync pipe at the end of the 'styles' task version myself.
Because you are using webpack plugin I assume the scripts task have to be handled differently from the styles task. You might try :
gulp.watch([settings.themeLocation + 'js/modules/*.js', settings.themeLocation + 'js/scripts.js'], gulp.series('waitForScripts', browserSync.reload));
and then no need for 'waitForScripts' task.