运行Gulp时出错

Question

我为我的项目设置gulp，并在运行时收到此消息。

 stream.js:74
  throw er; // Unhandled stream error in pipe.
  ^

 Error: EEXIST: file already exists, mkdir      
 'C:\Users\Theodosios\Desktop\AngularJs
 \Week4\conFusion\dist\fonts'
at Error (native)

我花了好几个小时看错了什么，但我不知道发生了什么。所以这是我的gulp代码。

var gulp = require('gulp'),
minifycss = require('gulp-minify-css'),
jshint = require('gulp-jshint'),
stylish = require('jshint-stylish'),
uglify = require('gulp-uglify'),
usemin = require('gulp-usemin'),
imagemin = require('gulp-imagemin'),
rename = require('gulp-rename'),
concat = require('gulp-concat'),
notify = require('gulp-notify'),
cache = require('gulp-cache'),
changed = require('gulp-changed'),
rev = require('gulp-rev'),
browserSync = require('browser-sync'),
del = require('del'),
ngannotate = require('gulp-ng-annotate');

gulp.task('jshint', function () {
return gulp.src('app/scripts/**/*.js')
    .pipe(jshint())
    .pipe(jshint.reporter('jshint-stylish', {beep: true}));
 });

 // Clean
 gulp.task('clean', function () {
return del(['dist']), del(['../json-server/public'], {force: true});
});

// Default task
gulp.task('default', ['clean'], function () {
gulp.start('usemin', 'imagemin', 'copyfonts');
});

gulp.task('usemin', ['jshint'], function () {
return gulp.src('./app/**/*.html')
    .pipe(usemin({
        css: [minifycss(), rev()],
        js: [ngannotate(), uglify(), rev()]
    }))
    .pipe(gulp.dest('dist/'))
    .pipe(gulp.dest('../json-server/public/'));
 });

// Images
gulp.task('imagemin', function () {
return del(['dist/images']), gulp.src('app/images/**/*')
    .pipe(cache(imagemin({optimizationLevel: 3, progressive: true,    
interlaced: true})))
    .pipe(gulp.dest('dist/images')).pipe(gulp.dest('../json-  
server/public/images'))
    .pipe(notify({message: 'Images task complete'}));
});

gulp.task('copyfonts', ['clean'], function () {
gulp.src('./bower_components/font-awesome/fonts/**/*.{ttf,woff,eof,svg}*')
    .pipe(gulp.dest('./dist/fonts')).pipe(gulp.dest('../json-
server/public/fonts'));
gulp.src('./bower_components/bootstrap/dist/fonts/**/*.{ttf,woff,eof,svg}*')
    .pipe(gulp.dest('./dist/fonts')).pipe(gulp.dest('../json-   
server/public/fonts'));
});

// Watch
gulp.task('watch', ['browser-sync'], function () {
// Watch .js files
gulp.watch('{app/scripts/**/*.js,app/styles/**/*.css,app/**/*.html}',   
['usemin']);
// Watch image files
gulp.watch('app/images/**/*', ['imagemin']);

});

gulp.task('browser-sync', ['default'], function () {
var files = [
    'app/**/*.html',
    'app/styles/**/*.css',
    'app/images/**/*.png',
    'app/scripts/**/*.js',
    'dist/**/*'
];

browserSync.init(files, {
    server: {
        baseDir: "dist",
        index: "index.html"
    }
});
// Watch any files in dist/, reload on change
gulp.watch(['dist/**']).on('change', browserSync.reload);
});

有什么想法吗？节点流管道中有一些错误，但无法看出错误在哪里。