What does NODE_ENV=production do?

Setting NODE_ENV=production causes these libraries and tools to behave as follows:

npm:

• install will not install devDependencies
• shrinkwrap will not install devDependencies
• prune will remove devDependencies

yarn:

• will not install packages listed in devDependencies

express:

• caches CSS files generated from CSS extensions
• generates less verbose error messages
• caches view templates by default
• sets the 'env' app setting to 'production' (the value of NODE_ENV)

express-session:

• warns if using MemoryStore in production

pug:

• disables debug compilations by default

react:

• less warnings, less slow bookkeeping

vue:

• less warning checks and error messages
• less performance measurements

sails:

• more efficient middleware, safe auto-migration strategy, minification, compression, no errors or stack-traces in response, less warnings

loopback:

• disables stack traces in JSON responses, disables API explorer

i18next:

• will serve minified version, and add cache headers

ghost:

• minification, concatenation, less error messages

bluebird:

• production doesn't do anything, but setting to development enables long stack traces and warnings

finalhandler (used by express):

• less verbose error messages

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These tools use NODE_ENV for selecting an environment/config:

• knex (migrations)
• kraken
• koa
• loopback
• meteor

These might use NODE_ENV sometime in the future:

• angular (offline compilation)

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Related resources:

• https://canho.me/2016/07/20/the-hidden-powers-of-node-env/