我试着在我的终端上运行gulp命令，在项目目录中，我有gulpfile.js，但我得到了错误，The following tasks did not complete: default, gulpSass; Did you forget to signal async completion，我试图寻找解决方案，但无济于事。
我检查了一些可能的原因，为什么我面临的问题，并实施了一些，但我仍然不断得到错误。
我尝试的一个可能的修复方法是在所有函数中使用async await，但它没有解决这个问题。
这是我的gulpfile.js**

var gulp     = require('gulp'),
sass         = require('gulp-sass'),
plumber      = require('gulp-plumber'),
notify       = require('gulp-notify'),
livereload   = require('gulp-livereload')
concat       = require('gulp-concat'),
uglify       = require('gulp-uglify'),

// Concat all js into one script
async function js ( cb ) {
  return await gulp.src(['./assets/js/lib/*.js','./assets/js/scripts/**/*.js'])
    .pipe(plumber(plumberErrorHandler))
    //.pipe(jshint())
    //.pipe(jshint.reporter('jshint-stylish'))
    .pipe(sourcemaps.init())
    .pipe(concat('scripts.min.js'))
    .pipe(uglify()) 
    .pipe(sourcemaps.write('../maps/'))
    .pipe(gulp.dest('./assets/js'))
    .pipe(livereload());

  cb();
}

// Sass compiler + Maps
async function sass ( cb ) {
  return await gulp.src('./assets/scss/*.scss')
    .pipe(plumber(plumberErrorHandler))
    .pipe(sassGlob())
    .pipe(sourcemaps.init())
    .pipe(sass({outputStyle: 'development'}))
    //.pipe(autoprefixer({
     // browsers: ['>1%'],
    //remove: false
    //}))
    .pipe(sourcemaps.write('./assets/maps'))
    .pipe(gulp.dest('.'))
    .pipe(livereload());

  cb();
}

// Watch for changes
async function watch ( cb ) {
  livereload.listen();
  return await gulp.watch('./assets/scss/**/*', ['sass']);
  return await gulp.watch('./assets/js/lib/**/*.js', ['js']);
  return await gulp.watch('./assets/js/scripts/**/*.js', ['js']);
  return await gulp.watch('./**/*.php').on('change', async function(file) {
    livereload.changed(file.path);
  });

  cb();
}

// Error handling/reporting
var plumberErrorHandler = { 
  errorHandler: notify.onError({
    title: 'Gulp',
    message: 'Error: <%= error.message %>'
  })
}

// Default
exports.default = gulp.series(js, sass, watch);