Gulpfile WP

const { src, dest, watch }  = require("gulp");
      sass                  = require("gulp-sass");
      minifyCSS             = require("gulp-csso");
      babel                 = require("gulp-babel");
      concat                = require("gulp-concat");
      uglify                = require("gulp-uglify");
      browserSync           = require("browser-sync").create();

function css() {
  return src("./sass/*.scss", { sourcemaps: true })
    .pipe(sass())
    .pipe(minifyCSS())
    .pipe(dest("./"), { sourcemaps: true })
    .pipe(browserSync.stream());
}

function js() {
  return src("./js/*.js", { sourcemaps: true })
    .pipe(
      babel({
        presets: ["@babel/env"],
      })
    )
    .pipe(uglify())

    .pipe(concat("build.min.js"))
    .pipe(dest("./js/min", { sourcemaps: true }))
}

function browser() {
  browserSync.init({
    proxy: "http://192.168.99.100:8000/",
    files: [
            "./**/*.php",
            "./**/*.js",
            "./**/*.scss",
           ]
  });

  watch("./sass/**/*.scss", css);
  watch("./js/*.js", js).on("change", browserSync.reload);
}

exports.css = css;
exports.js = js;
exports.default = browser;