Why Gulp does not ignore the file? - node.js

Question

My project structure:
build
public
assets
css
app.css
vendor.css
js
app.js
vendor.js
index.html
src
assets
styles
main.styl
coffee
main.coffee
index.jade
I have a task to build a library of Bower in two files : vendor.css and vendor.js:
var uglify = require('gulp-uglify');
var minifyCss = require('gulp-minify-css');
var mainBowerFiles = require('gulp-main-bower-files');
var filter = require('gulp-filter');
var concat = require('gulp-concat');
var connect = require('gulp-connect');
gulp.task('bower', ['clean'], function () {
var jsFilter = filter('**/*.js', { restore: true });
var cssFilter = filter('**/*.css', { restore: true });
return gulp.src('./bower.json')
.pipe(mainBowerFiles())
.pipe(cssFilter)
.pipe(concat('vendor.css'))
.pipe(minifyCss())
.pipe(gulp.dest(path.dist.css))
.pipe(cssFilter.restore)
.pipe(jsFilter)
.pipe(concat('vendor.js'))
.pipe(uglify())
.pipe(gulp.dest(path.dist.js))
.pipe(jsFilter.restore)
.pipe(connect.reload());
});
Here's my task on cleaning of temporary folders when you change files in the src folder:
var del = require('del');
...
gulp.task('clean', function () {
return del(['build', 'public/**', '!public/**/vendor.{js,css}']);
});
That must delete the build folder and all the contents of the public directory, except the vendor.css and vendor.js that are in the folder public/assets/css and public/assets/js.
This is done in order to not build a library of bower at each change of the file, because it takes 3-4 seconds (by the way, is this normal?), but only at the first start or change bower.json ( running separate watcher).
But somehow, the files vendor.js and vendor.css also removed. With gulp-tap I got a list of files:
List of files
What am i doing wrong?

Answer 1

According to https://github.com/sindresorhus/del#beware you need also exclude sub-directories, otherwise del will delete all.
So, you can use something like this:
del([.., 'public/**/*', '!public/{dir_1,dir_2}', '!test/**/vendor{.css,.js}']);