CoNext.js is a small function for JavaScript to wrap a generator
function with Co for use as request handlers and middlewares.
Calls the last argument (usually called next) if there was an error, but not
if the generator finishes successfully. Useful with Express routes.
npm install co-nextCoNext.js follows semantic versioning, so feel free to
depend on its major version with something like >= 1.0.0 < 2 (a.k.a ^1.0.0).
var next = require("co-next")
var app = require("express")()
app.get("/", next(function*(req, res, next) {
if (req.account == null) throw new Error("Unauthorized")
res.send("Hello, world!")
}))In the above example, the thrown error will be passed to next, which in
Express's case calls the error handling middleware later on. If the generator succeeds, the next callback will not be called.
If you need to, like in middleware handlers, you can always call next
yourself:
app.use(next(function*(req, res, next) {
var account = yield accounts.read(req.session.accountId)
if (account == null) return void next(new Error("Unauthorized"))
req.account = account
next()
}))CoNext.js is released under a Lesser GNU Affero General Public License, which in summary means:
- You can use this program for no cost.
- You can use this program for both personal and commercial reasons.
- You do not have to share your own program's code which uses this program.
- You have to share modifications (e.g. bug-fixes) you've made to this program.
For more convoluted language, see the LICENSE file.
Andri Möll typed this and the code.
Monday Calendar supported the engineering work.
If you find CoNext.js needs improving, please don't hesitate to type to me now at [email protected] or create an issue online.