Environment Gulp Sass BrowserSync

gulpfile.js

var gulp        =  require('gulp');
var browserSync =  require('browser-sync').create();
var sass        =  require('gulp-sass');

//Compilar sass em CSS & injetar no navegador
gulp.task('sass', function(){
    return gulp.src(['src/scss/bootstrap.scss', 'src/scss/*.scss'])
        .pipe(sass())
        .pipe(gulp.dest("src/css"))
        .pipe(browserSync.stream());
});

//Mover JS para src/css
gulp.task('js', function() {

    return gulp.src(['node_modules/bootstrap/dist/js/bootstrap.min.js', 
        'node_modules/jquery/dist/jquery.min.js', 
        'node_modules/popper.js/dist/umd/popper.min.js'])
        .pipe(gulp.dest("src/js"))
        .pipe(browserSync.stream());

});

//Seridor para compilar HTML/CSS
gulp.task('serve', ['sass'], function() {

    browserSync.init({
        server: "./src"
    });

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

//fim
gulp.task('default', ['js', 'serve']);