Gulp throws an error on gulp-clean-css, can anyone help?

Question

npm

Reinstalling gulp-clean-css did not help, the same with node_modules, reinstalling did not work.
This is what
Gulpfile.js outputs

var gulp           = require('gulp'),
    gutil          = require('gulp-util' ),
    sass           = require('gulp-sass'),
    browserSync    = require('browser-sync'),
    concat         = require('gulp-concat'),
    uglify         = require('gulp-uglify'),
    cleanCSS       = require('gulp-clean-css'),
    rename         = require('gulp-rename'),
    rigger         = require('gulp-rigger'),
    del            = require('del'),
    imagemin       = require('gulp-imagemin'),
    cache          = require('gulp-cache'),
    autoprefixer   = require('gulp-autoprefixer'),
    notify         = require('gulp-notify');

// Скрипты проекта
gulp.task('scripts', function() {
  return gulp.src([
    'src/libs/jquery/jquery.min.js',
    'src/js/common.js', // Всегда в конце
    ])
  .pipe(concat('scripts.min.js'))
  .pipe(uglify())
  .pipe(gulp.dest('src/js'))
  .pipe(browserSync.reload({stream: true}));
});

gulp.task('browser-sync', function() {
  browserSync({
    server: {
      baseDir: 'src'
    },
    notify: false
  });
});

gulp.task('sass', function() {
  return gulp.src('src/sass/**/*.scss')
  .pipe(rename({suffix: '.min', prefix : ''}))
  .pipe(autoprefixer(['last 15 versions']))
  .pipe(cleanCSS())
  .pipe(gulp.dest('src/css'))
  .pipe(browserSync.reload({stream: true}));
});

gulp.task('watch', ['sass', 'scripts', 'browser-sync'], function() {
  gulp.watch('src/sass/**/*.scss', ['sass']);
  gulp.watch(['libs/**/*.js', 'src/js/common.js'], ['scripts']);
  gulp.watch('src/*.html', browserSync.reload);
});

gulp.task('imagemin', function() {
  return gulp.src('src/img/**/*')
  .pipe(cache(imagemin()))
  .pipe(gulp.dest('build/img'));
});

gulp.task('build', ['removedist', 'imagemin', 'sass', 'scripts'], function() {

  var buildFiles = gulp.src([
    'src/*.html'
  ]).pipe(rigger())
  .pipe(gulp.dest('build'));

  var buildCss = gulp.src([
    'src/css/main.min.css',
    ]).pipe(gulp.dest('build/css'));

  var buildJs = gulp.src([
    'src/js/scripts.min.js'
    ]).pipe(gulp.dest('build/js'));

  var buildFonts = gulp.src([
    'src/fonts/**/*'
    ]).pipe(gulp.dest('build/fonts'));

});

gulp.task('removedist', function() { return del.sync('build'); });
gulp.task('clearcache', function () { return cache.clearAll(); });

gulp.task('default', ['watch']);

package.json

"devDependencies": {
    "browser-sync": "^2.18.8",
    "del": "^2.2.2",
    "gulp": "^3.9.1",
    "gulp-autoprefixer": "^3.1.1",
    "gulp-cache": "^0.4.6",
    "gulp-clean-css": "^3.0.4",
    "gulp-concat": "^2.6.1",
    "gulp-imagemin": "^3.2.0",
    "gulp-notify": "^3.0.0",
    "gulp-rename": "^1.2.2",
    "gulp-rigger": "^0.5.8",
    "gulp-sass": "^3.1.0",
    "gulp-uglify": "^2.1.2",
    "gulp-util": "^3.0.8"
  }

main scss

Answer 1

You don't seem to have compiled scss to css.