A tiny JavaScript debugging utility that works in Node.js and browsers. Use environment variables to control logging, so there are no ridiculous console log statements in production.
This is based on debug. It's been rewritten to use contemporary JS.
Featuring:
- Use exports field in
package.json
to choose node JS or browser version - ESM only
npm i -D @bicycle-codes/debug
Use this with vite in the browser or in node.
This is ergonomic with the vite bundler. This module will look for an env variable prefixed with VITE_
:
VITE_DEBUG=fooo
If you initialize this without a namespace, then it checks import.meta.env.DEV
:
import Debug from '@bicycle-codes/debug'
const debug = Debug()
debug('debug works') // check if `import.meta.env.DEV`
You can pass in an env variable of VITE_DEBUG_MODE
, and then debug
will
check for that mode in vite.
VITE_DEBUG_MODE=staging vite build --mode staging
If you are in production (import.meta.env.PROD
) and there is no VITE_DEBUG
env var, then this exports a noop, so debug will do nothing, and your bundle will be smaller.
In your JS code:
import { createDebug } from '@bicycle-codes/debug'
const debug = createDebug('fooo')
debug('debug works')
You would start that script with a VITE_DEBUG=fooo
env var to see the log statements.
If you call this without a namespace
argument, it will look at the value of import.meta.env.DEV
. If you are in DEV mode, then it will log things in a random color:
const debugTwo = createDebug()
// this is only logged if `import.meta.env.DEV` is true
debugTwo('testing debug 2')
setTimeout(() => {
debug2('log again')
}, 1000)
Run your script with an env variable, DEBUG
.
// in node JS
import createDebug from '@bicycle-codes/debug/node'
const debug = createDebug('fooo')
debug('testing')
Call this with an env var of DEBUG=fooo
DEBUG=fooo node ./test/fixture/node.js
If you are in dev mode (process.env.NODE_ENV === 'development'
), then this will log things in a random color if you don't initialize it with a namespace --
import createDebug from '@bicycle-codes/debug'
const debug = createDebug()
debug('hello')
Run the script like this:
NODE_ENV=development node ./my-script.js
Configure what NODE_ENV
value will trigger logging by overriding the shoudlLog
function:
// in node only
import Debug from '@bicycle-codes/debug'
Debug.shouldLog = function (NODE_ENV) {
return NODE_ENV === 'example'
}
const debug = Debug()
// this will log iff we start this like
// NODE_ENV="example" node my-program.js
debug('testing')
Start a vite
server and log some things. This uses the example directory.
npm start
Run tests:
npm test