Rails 5 Heroku deploy error: ExecJS::ProgramError: SyntaxError: Unexpected token: name (autoRegisterNamespace)

Question

When trying to deploy a rails 5 app to heroku, I get the following error, when it reaches Running: rake assets:precompile:

remote:        ExecJS         


        

Answer 1

As the Uglifier official documentation says (https://github.com/lautis/uglifier):

"The experimental ES6 syntax support can be enabled by passing :harmony => true option to Uglifier."

Uglifier.compile(js, harmony: true)

So replace in config/environments/production.rb.

config.assets.js_compressor = :uglifier

with

config.assets.js_compressor = Uglifier.new(harmony: true)