define-error
v1.1.0
Published
Define errors without frills, but with stack traces and instanceof support.
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define-error
Define errors without frills, but with stack traces and instanceof support.
example
First, create and expose a singleton that defines your errors such as errors.js
:
var defineError = require('define-error')
module.exports.DatabaseError = defineError('DatabaseError')
module.exports.HttpResponseError = defineError('HttpResponseError', function (message, code) {
this.code = code
})
Then use them:
var assert = require('assert'),
DatabaseError = require('./errors').DatabaseError,
HttpResponseError = require('./errors').HttpResponseError
function query () {
throw new DatabaseError('No database to query silly')
}
function request () {
throw new HttpResponseError('Nobody out there', 404)
}
try {
query()
}
catch (err) {
assert(err instanceof DatabaseError)
assert(err instanceof Error)
console.error(err)
}
try {
request()
}
catch (err) {
assert(err instanceof HttpResponseError)
assert(!(err instanceof DatabaseError))
assert(err instanceof Error)
assert(err.code)
console.error(err)
}
api
var defineError = require('define-error')
var CustomError = defineError('CustomError' [, initFunc])
Create an error constructor, CustomError(message)
. Error
will be in the prototype chain. If an initFunc
function is provided, it will be called in the context of the error being created with all arguments that were passed to the error constructor. This will happen after the message
and stack
properties are set on the error object.
install
With npm do:
npm install --save define-error
testing
npm test
Or to run tests in phantom: npm run phantom
coverage
npm run view-cover
This will output a textual coverage report.
npm run open-cover
This will open an HTML coverage report in the default browser.