# Failed yarn dev + gulp

**URL:** <https://forum.ghost.org/t/failed-yarn-dev-gulp/3048>\
**Category:** Developer help\
**Created:** [September 13, 2018, 4:06am UTC](https://forum.ghost.org/t/failed-yarn-dev-gulp/3048 "2018-09-13T04:06:21Z")\
**Posts on this page:** 4\
**Page:** 1

<div class="post-metadata">

**Author:** ![javiermendonca](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.ghost.org/javiermendonca/32/1489_2.png) [@javiermendonca](https://forum.ghost.org/u/javiermendonca)\
**Post date:** [September 13, 2018, 4:06am UTC](https://forum.ghost.org/t/failed-yarn-dev-gulp/3048/1 "2018-09-13T04:06:21Z")

</div>

Hi guys,

I am customizing a Casper theme and I can’t get it zipped. Gulp just fails no matter what I do. Here are the logs:

```
$ yarn dev
yarn run v1.9.4
$ gulp

assert.js:85
  throw new assert.AssertionError({
  ^
AssertionError: Task function must be specified
    at Gulp.set [as _setTask] (/home/javier/opt/ghost/content/themes/Casper/node_modules/undertaker/lib/set-task.js:10:3)
    at Gulp.task (/home/javier/opt/ghost/content/themes/Casper/node_modules/undertaker/lib/task.js:13:8)
    at Object.<anonymous> (/home/javier/opt/ghost/content/themes/Casper/gulpfile.js:27:6)
    at Module._compile (module.js:556:32)
    at Object.Module._extensions..js (module.js:565:10)
    at Module.load (module.js:473:32)
    at tryModuleLoad (module.js:432:12)
    at Function.Module._load (module.js:424:3)
    at Module.require (module.js:483:17)
    at require (internal/module.js:20:19)
    at execute (/home/javier/opt/ghost/content/themes/Casper/node_modules/gulp/node_modules/gulp-cli/lib/versioned/^4.0.0-alpha.2/index.js:36:18)
    at Liftoff.handleArguments (/home/javier/opt/ghost/content/themes/Casper/node_modules/gulp/node_modules/gulp-cli/index.js:175:63)
    at Liftoff.execute (/home/javier/opt/ghost/content/themes/Casper/node_modules/liftoff/index.js:203:12)
    at module.exports (/home/javier/opt/ghost/content/themes/Casper/node_modules/flagged-respawn/index.js:51:3)
    at Liftoff.<anonymous> (/home/javier/opt/ghost/content/themes/Casper/node_modules/liftoff/index.js:195:5)
    at /home/javier/opt/ghost/content/themes/Casper/node_modules/liftoff/index.js:165:9
error Command failed with exit code 1.
info Visit https://yarnpkg.com/en/docs/cli/run for documentation about this command.

```

I synced my gulpfile.js to the latest in case anything was broken in the previous version. I don’t see what’s wrong int here. Any ideas?

Thanks

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<div class="post-metadata">

**Author:** ![enoter](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.ghost.org/enoter/32/1243_2.png) [@enoter](https://forum.ghost.org/u/enoter)\
**Post date:** [September 13, 2018, 7:54am UTC](https://forum.ghost.org/t/failed-yarn-dev-gulp/3048/2 "2018-09-13T07:54:11Z")

</div>

Run **yarn install** and then **yarn dev** 🙂

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<div class="post-metadata">

**Author:** ![javiermendonca](https://sea1.discourse-cdn.com/flex015/user_avatar/forum.ghost.org/javiermendonca/32/1489_2.png) [@javiermendonca](https://forum.ghost.org/u/javiermendonca)\
**Post date:** [September 13, 2018, 8:24am UTC](https://forum.ghost.org/t/failed-yarn-dev-gulp/3048/3 "2018-09-13T08:24:38Z")

</div>

Yeah I was doing so but I was getting this error with yarn dev…

So I tried reinstalling ghost in another folder, resynced gulpfile.js and package.json and then it worked without problems… I think I was having some weird setup happening with my ghost installation.

Now it works just fine 🙂

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<div class="post-metadata">

**Author:** ![system](https://us1.discourse-cdn.com/flex015/uploads/ghost2/original/2X/b/ba9ce5100b8bb264586f4f572545596b2ce3f081.png) [@system](https://forum.ghost.org/u/system)\
**Post date:** [September 27, 2018, 8:24am UTC](https://forum.ghost.org/t/failed-yarn-dev-gulp/3048/4 "2018-09-27T08:24:47Z")

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Closed on September 27, 2018, 8:24am UTC

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