A simple Error type manager for expressjs apps


ErrorManager is a very small utility for managing types of Errors in an ExpressJS application.

This is pretty alpha so design may change as I use tweak it in actual real world usage.

It's Coffeescript:

ErrorManager = require "error-manager"

# ==================== 
# Create a new types of errors usable in the application
# ==================== 
ErrorManager.create "MyCustomError"
ErrorManager.create "DatabaseBlewUp"

# ==================== 
# Create a custom express error handling middleware 
# ==================== 
app.use (err, req, res, next) ->
    # errors can be checked  using instanceof
    if ! err instanceof ErrorManager.MyCustomError
        return next(err)

    res.send "Got MyCustomError"

app.use (err, req, res, next) ->
    # errors can also be checked with a is(), which is injected by ErrorManager
    # into the Error object's prototype
    if == false
        return next(err)

    res.send "Oh snap! The DB blew up."

# ... more error handling middle ware

It is meant to be installed as part of your package.json via NPM. Just add a "error-manager": "latest" to the dependencies section.