gulpfile.js

const gulp = require('gulp'); 
const sass = require('gulp-sass'); 
const browserSync = require('browser-sync'); 

gulp.task('sass', gulp.series( () =>{
    return gulp.src([
        'node_modules/bootstrap/scss/bootstrap.scss', 
        'src/scss/*.scss'                             
    ])
    .pipe(sass({outputStyle: 'compressed'}))
    .pipe(gulp.dest('src/css'))             
    .pipe(browserSync.stream());            
}));

gulp.task('js',gulp.series( () => {
    return gulp.src([
        'node_modules/bootstrap/dist/js/bootstrap.min.js',    
        'node_modules/jquery/dist/jquery.min.js',           
        'node_modules/@popperjs/core/dist/umd/popper.min.js'     
    ])
    .pipe(gulp.dest('src/js'))   
    .pipe(browserSync.stream()); 
}));

gulp.task('font-awesome',gulp.series( () => { 
    return gulp.src('node_modules/font-awesome/css/font-awesome.min.css') 
        .pipe(gulp.dest('src/css'));
}));

gulp.task('fonts',gulp.series( () => {
    return gulp.src('node_modules/font-awesome/fonts/*') 
        .pipe(gulp.dest('src/fonts'))
}));

gulp.task('serve',gulp.series( ['sass'], () => { 
    browserSync.init({                          
        server: {                              
            baseDir: './src'   
        }
    });
}));

gulp.watch([                                               
    'node_modules/bootstrap/scss/bootstrap.scss',           
    'src/scss/*.scss'                                       
], gulp.parallel( ['sass'] ));                              
                                                            
gulp.watch(['src/*.html']).on('change', browserSync.reload);


gulp.task('default', gulp.series(['font-awesome','fonts','js','serve']));