blob: 20139f1ec14bdf1a5471f18dd286f6e1e3f51a6b (
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/**
* If the middleware function does declare receiving the `next` callback
* assume that it's synchronous and invoke `next` ourselves
*/
function noCallbackHandler(ctx, connectMiddleware, next) {
connectMiddleware(ctx.req, ctx.res)
return next()
}
/**
* The middleware function does include the `next` callback so only resolve
* the Promise when it's called. If it's never called, the middleware stack
* completion will stall
*/
function withCallbackHandler(ctx, connectMiddleware, next) {
return new Promise((resolve, reject) => {
connectMiddleware(ctx.req, ctx.res, err => {
if (err) reject(err)
else resolve(next())
})
})
}
/**
* Returns a Koa middleware function that varies its async logic based on if the
* given middleware function declares at least 3 parameters, i.e. includes
* the `next` callback function
*/
function koaConnect(connectMiddleware) {
const handler = connectMiddleware.length < 3
? noCallbackHandler
: withCallbackHandler
return function koaConnect(ctx, next) {
return handler(ctx, connectMiddleware, next)
}
}
module.exports = koaConnect
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