Gulp doesn't create link to a folder - gulp

Question

Can not create a symbolic link to the /var/www/project/bower_components/bootstrap/less/mixins folder via Gulp JS. I tried to specify the desired path via the nodeJS.
VARIANT 1
CODE:
var gulp = require('gulp');
var path = require('path');
var debug = require('gulp-debug');
var symlink = require('gulp-sym');
gulp.task('symlink-deploy', function () {
var mixins = gulp
.src('' + path.resolve() + 'bower_components/bootstrap/less/mixins/')
.pipe(symlink('' + path.resolve() + 'assets/less/'))
.pipe(debug({title: 'unicorn:'}));
return Promise.all([mixins]);
});
gulp.task('default', ['symlink-deploy']);
RESULT:
user#user-ThinkPad-Edge-E545:/var/www/project$ gulp symlink-deploy
[17:18:44] Using gulpfile /var/www/project/gulpfile.js
[17:18:44] Starting 'symlink-deploy'...
[17:18:44] Finished 'symlink-deploy' after 28 ms
events.js:141
throw er; // Unhandled 'error' event
^
Error: EISDIR: illegal operation on a directory, read
at Error (native)
user#user-ThinkPad-Edge-E545:/var/www/project$
I have also was tried set path manually:
VARIANT 2
CODE:
var gulp = require('gulp');
var path = require('path');
var debug = require('gulp-debug');
var symlink = require('gulp-sym');
gulp.task('symlink-deploy', function () {
var mixins = gulp
.src('/home/user/www/project/bower_components/bootstrap/less/mixins')
.pipe(symlink('/home/user/www/project/assets/less'))
.pipe(debug({title: 'unicorn:'}));
return Promise.all([mixins]);
});
gulp.task('default', ['symlink-deploy']);
RESULT:
user#user-ThinkPad-Edge-E545:/var/www/project$ gulp symlink-deploy
[17:57:55] Using gulpfile /var/www/project/gulpfile.js
[17:57:55] Starting 'symlink-deploy'...
[17:57:55] Finished 'symlink-deploy' after 27 ms
events.js:141
throw er; // Unhandled 'error' event
^
Error: Destination file exists (/home/user/www/project/assets/less) - use force option to replace
at Transform._transform (/var/www/project/node_modules/gulp-sym/index.js:55:26)
at Transform._read (/var/www/project/node_modules/gulp-sym/node_modules/readable-stream/lib/_stream_transform.js:184:10)
at Transform._write (/var/www/project/node_modules/gulp-sym/node_modules/readable-stream/lib/_stream_transform.js:172:12)
at doWrite (/var/www/project/node_modules/gulp-sym/node_modules/readable-stream/lib/_stream_writable.js:237:10)
at writeOrBuffer (/var/www/project/node_modules/gulp-sym/node_modules/readable-stream/lib/_stream_writable.js:227:5)
at Transform.Writable.write (/var/www/project/node_modules/gulp-sym/node_modules/readable-stream/lib/_stream_writable.js:194:11)
at write (/var/www/project/node_modules/vinyl-fs/node_modules/readable-stream/lib/_stream_readable.js:623:24)
at flow (/var/www/project/node_modules/vinyl-fs/node_modules/readable-stream/lib/_stream_readable.js:632:7)
at DestroyableTransform.pipeOnReadable (/var/www/project/node_modules/vinyl-fs/node_modules/readable-stream/lib/_stream_readable.js:664:5)
at emitNone (events.js:67:13)
user#user-ThinkPad-Edge-E545:/var/www/project$
Can't understand why it is't working.