rake db:create - Could not find a JavaScript runtime

Question

Here is the error I get:

sergio@sergio-VirtualBox:~/blog$ rake db:create
rake aborted!
Could not find a JavaScript runtime. See https://github.com/sstephenson/execjs for a list of available runtimes.

(See full trace by running task with --trace)

sergio@sergio-VirtualBox:~/blog$

So after some searching it seems I need to install a Javascript runtime for Ruby.

Is there a difference between the many different options? It seems Node.js is the easiest to install, will this come back to bite me or is this choice OK?

This answer, seems to be what I'm looking for but I don't know how to make use of it. Where do I find this "gemfile" and is it a per rails project file or a global ruby file? I'm very confused and can't seem to get my bearings and multiple answers contradict each other and don't solve the issue.

Add this to your Gemfile

gem 'therubyracer', require: "v8"

and run

bundle install

djlumley · Accepted Answer · 2012-01-29 22:58:08Z

54

Ruby itself doesn't require a JS runtime, but a default new Rails application does.

There's a file called Gemfile in your main application directory (i.e. per Rails project) which is a list of gems required for your project that you can install using bundle install.

Adding the line gem 'therubyracer' and then bundle install will install the ruby racer JS runtime, which I've found to be the simplest if you're on a 64bit OS.

You can find more information about your Gemfile at the Bundler site.

answered Jan 29, 2012 at 22:58

djlumley

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1 Comment

Michael Z Over a year ago

More detailed explanation: stackoverflow.com/questions/6282307/…

Ben Zhang · Accepted Answer · 2012-01-29 22:57:20Z

6

Have you installed Node.js on your computer yet? It needs to be installed on your computer as well.

here is the link to download, http://nodejs.org/#download

answered Jan 29, 2012 at 22:57

Ben Zhang

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Brady Holt Over a year ago

Are you sure about that? Why would rake need Node.js?

Community · Accepted Answer · 2017-05-23 12:33:32Z

1

There are several fairly similar options such rubytheracer, node and execjs.

rubytheracer has fallen out of favor due to its code size. Vendors such as Heroku (for rails) actively discourage it.

I currently recommend node.js

More info at Rails - Could not find a JavaScript runtime?

edited May 23, 2017 at 12:33

CommunityBot

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answered Apr 17, 2013 at 13:53

Michael Durrant

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1 Comment

Winfield Trail Over a year ago

Fallen out of favor due to its code size? In the Rails crowd?! Surely you jest, sir.

Buminda · Accepted Answer · 2013-03-16 14:49:39Z

0

insert gem 'therubyracer' in Gemfile in a new line 1. run

gem install therubyracer -v '0.11.4'

run

bundle install

This will work

answered Mar 16, 2013 at 14:49

Buminda

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Comments

Jesse · Accepted Answer · 2013-05-17 01:09:35Z

0

I had the same error, but then I reinstalled Ruby193 with all the checkboxes (Tc/Tk, associate rb, and add to PATH).

And then deleted the GEMFile.lock

Edited the Gemfile whereever I saw gem therubyracer, I changed it to: gem therubyracer, :platform => :ruby

Then bundle install
Then rake db:drop
Then rake db:create
Then rake db:migrate

and so on

edited May 17, 2013 at 1:09

Jesse

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answered May 17, 2013 at 0:52

FahadJ

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Aeon · Accepted Answer · 2013-01-26 19:12:33Z

-1

Just gem install "therubyracer" and it just works.

answered Jan 26, 2013 at 19:12

Aeon

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