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

score 54 · Accepted Answer · answered Jan 29 '12 at 22:58

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.

More detailed explanation: http://stackoverflow.com/questions/6282307/execjs-and-could-not-find-a-javascript-runtime — Michael Z, Jul 28 '12 at 08:20

score 6 · Answer 2 · answered Jan 29 '12 at 22:57

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 '12 at 22:57

Ben Zhang

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Are you sure about that? Why would rake need Node.js? – Brady Holt Jul 26 '12 at 21:48

score 1 · Answer 3 · edited May 23 '17 at 12:33

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 '17 at 12:33

Community

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answered Apr 17 '13 at 13:53

Michael Durrant

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Fallen out of favor *due to its code size?* In the Rails crowd?! Surely you jest, sir. – Winfield Trail Oct 27 '14 at 19:04

score 0 · Answer 4 · answered Mar 16 '13 at 14:49

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 '13 at 14:49

Buminda

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score 0 · Answer 5 · edited May 17 '13 at 01:09

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 '13 at 01:09

Jesse

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answered May 17 '13 at 00:52

FahadJ

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score -1 · Answer 6 · answered Jan 26 '13 at 19:12

-1

Just gem install "therubyracer" and it just works.

answered Jan 26 '13 at 19:12

Aeon

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rake db:create - Could not find a JavaScript runtime

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