gulpfile.js

var gulp = require("gulp");
var browserSync = require("browser-sync");
var reload = browserSync.reload;
var plumber = require("gulp-plumber");
var notify = require("gulp-notify");
var sourcemaps = require("gulp-sourcemaps");
var sass = require("gulp-sass");

gulp.task("sass", function() {
    return gulp.src("./public/res/styles/*.scss")
        .pipe(plumber({errorHandler: notify.onError("Error: <%= error.message %>")}))
        .pipe(sourcemaps.init())
        .pipe(sass({includePaths: ["node_modules/compass-mixins/lib"]}))
        .pipe(sourcemaps.write())
        .pipe(gulp.dest("./public/res/styles"))
        .pipe(reload({stream: true}));
});

gulp.task("serve", ["sass"], function() {
    browserSync({server: "./public"});

    gulp.watch("public/res/styles/*.scss", ["sass"]);
    gulp.watch(["public/**/*", "!public/**/*.scss", "!public/**/*.css"])
        .on("change", reload);
});

gulp.task("default", ["serve"]);