I'm trying to deploy a JS/node/express/webpack application to Heroku.

I need Heroku to install my devDependencies because it includes webpack, which is necessary to build the client-side files of my project.

However, I cannot get Heroku to read my devDependencies.

I have read everywhere that setting NPM_CONFIG_PRODUCTION = 'false' will fix this, but it does not. Here are my config vars for my Heroku build (taken from the build log):

NPM_CONFIG_PRODUCTION=false    // I set this from both the heroku-cli and the web ui
NPM_CONFIG_LOGLEVEL=error
NODE_VERBOSE=false
NODE_ENV=production
NODE_MODULES_CACHE=true

Then the logs go on to say:

-----> Pruning devDependencies
       Skipping because NPM_CONFIG_PRODUCTION is 'false'

Isn't the desired behavior that devDependencies will be install when this var is set to false?