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Wrap each middleware in array with provided middleware #51

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Wrap each middleware in array with provided middleware #51

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61b0e20
wrapp all mw with given fn
fl0w Mar 24, 2016
b8eb6a0
add README paragraph
fl0w Mar 24, 2016
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4 changes: 4 additions & 0 deletions Readme.md
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Expand Up @@ -22,6 +22,10 @@ $ npm install koa-compose

Compose the given middleware and return middleware.

### compose([a, b, c, ...], wrapper)

Compose the given middleware, wrap all in given wrapper, and return middleware.

## License

MIT
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8 changes: 6 additions & 2 deletions index.js
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Expand Up @@ -14,12 +14,14 @@ module.exports = compose
* of all those which are passed.
*
* @param {Array} middleware
* @param {Function} wrapper
* @return {Function}
* @api public
*/

function compose (middleware) {
function compose (middleware, wrapper) {
if (!Array.isArray(middleware)) throw new TypeError('Middleware stack must be an array!')
if (wrapper && typeof wrapper !== 'function') throw new TypeError('Profiler needs be a function!')
for (const fn of middleware) {
if (typeof fn !== 'function') throw new TypeError('Middleware must be composed of functions!')
}
Expand All @@ -37,7 +39,9 @@ function compose (middleware) {
function dispatch (i) {
if (i <= index) return Promise.reject(new Error('next() called multiple times'))
index = i
const fn = middleware[i] || next
let fn
if (wrapper) fn = middleware[i] ? wrapper(middleware[i]) : next
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haha why not just

let fn = middleware[i] || next
if (wrapper) fn = wrapper(fn)

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We don't want to wrap next.

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why not?

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next is guaranteed to be a function in conformance with standard Koa practice. It's not coming from the user 90% of the time. If you use co.wrap as a wrapper, you don't want it processing next.

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Oh, also, a profiler shouldn't run on the next function, that just wouldn't make sense.

else fn = middleware[i] || next
if (!fn) return Promise.resolve()
try {
return Promise.resolve(fn(context, function next () {
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