Warning: node.js detection failed, sbt will use the Rhino based Trireme JavaScript engine

Question

I'm new to Play framework. Please explain the meaning of the below warning.

Warning: node.js detection failed, sbt will use the Rhino based Trireme JavaScript engine instead to run JavaScript assets compilation, which in some cases may be orders of magnitude slower than using node.js

I don't want anything that slow down my application so please advice if I should change the JS Engine to Node.js, but my PlayFramework project is using Java on the server side.

Answer 1

You need to install Node.js and then tell the sbt/java engine to use it.

  brew install node

Edit .bash_profile and add:

   export SBT_OPTS="${SBT_OPTS} -Dsbt.jse.engineType=Node -Dsbt.jse.command=$(which node)"

This eliminated the warning for me on OSX

Answer 2

In Windows:

• Install node.js
• Go to Control Panel - System and Security - System - Advanced system settings
• Click Environment Variables...
• Search in System variables for SBT_OPTS
  • If such exists, click Edit... and concatenate -Dsbt.jse.engineType=Node to Variable value
  • If such does NOT exist, click New... and write SBT_OPTS to Variable name and -Dsbt.jse.engineType=Node to Variable value
• Click OK - OK - OK
• Restart any command prompt (cmd, PowerShell) that is currently running Play Framework

Answer 3

in ubuntu

curl -sL https://deb.nodesource.com/setup | sudo bash -

sudo apt-get install -y nodejs

then add as above to your .profile in your home directory

export SBT_OPTS="${SBT_OPTS} -Dsbt.jse.engineType=Node -Dsbt.jse.command=$(which node)"

then

 . ./.profile 

to reload your .profile

For a more flexible install using node version manager check the following tutorial: how to install node js on an ubuntu 14.04 server

Build again and the warning about using the Trireme stuff should be gone.