initial commit 1.0.0

Author: jkyberneees

README.md

@@ -1,2 +1,107 @@
 # middleware-if-unless
-Invokes connect-like middleware if / unless routing criteria matches. Inspired on express-unless module.
+Invokes connect-like middleware if / unless routing criteria matches. Inspired on [express-unless](https://www.npmjs.com/package/express-unless) module.  
+
+## Main features
+- Advanced routes matching capabilities. Uses [find-my-way](https://www.npmjs.com/package/find-my-way) or any compatible router to match the routes. 
+- `iff`: execute middleware only if the routes matches. Ideal use case: API gateways (see: [k-fastify-gateway](https://www.npmjs.com/package/k-fastify-gateway))
+- `unless`: execute middleware always unless the routes matches.
+- Arbitraty chaining of iff -> unless of vice-versa.
+- Low overhead, crazy fast implementation. 
+
+
+# Usage example
+How to extend any connect-like middleware:
+```js 
+const iu = require('middleware-if-unless')()
+
+const middleware = function (req, res, next) {
+  res.body = 'hit'
+
+  return next()
+}
+
+// extend middleware with iff/unless capabilities
+iu(middleware)
+```
+## unless
+Execute middleware unless routing restrictions matches:
+```js
+const app = require('express')()
+app.use(middleware.unless([
+  '/not/allowed/to/hit'
+]))
+
+...
+```
+In this example, all requests except `[GET] /not/allowed/to/hit` will cause the middleware to be executed.
+
+## if
+Execute middleware only if routing restrictions matches:
+```js
+const app = require('express')()
+app.use(middleware.iff([
+  {
+      methods: ['POST', 'DELETE', 'PUT', 'PATCH'],
+      url: '/tasks/:id'
+  }
+]))
+
+...
+```
+### Chaining
+You can optionally chain iff -> unless or vice-versa:
+```js
+app.use(middleware
+  .iff(req => req.url.startsWith('/pets'))  // 4 check
+  .iff([                                    // 3 check
+    '/pets/*',
+    '/pets/:id/*'
+  ]).unless([                               // 2 check
+    '/pets/:id/owners',
+    {
+      url: '/pets/:id', methods: ['DELETE'] 
+    }
+  ]).unless(req => req.url.endsWith('.js')) // 1 check
+)
+```
+# Configuration
+## module
+```js
+const iu = require('middleware-if-unless')(
+  // optional router configuration: 
+  // https://www.npmjs.com/package/find-my-way#findmywayoptions
+  {
+  }
+  , 
+  // optional router factory:
+  // allows to override find-my-way as default router
+  function(opts){}
+)
+```
+## iff / unless
+Both methods share the same configuration format:
+
+### - routing criteria is a function 
+```js
+middleware.iff(req => req.url.startsWith('/pets'))
+```
+### - routing criteria is an array of routes
+```js
+middleware.iff([
+  '/login', // if string is passed, the GET method is inferred
+  {
+    methods: ['DELETE', 'POST', '...'],
+    url: '/task/:id/*'
+  }
+])
+```
+### - routing criteria is an object
+```js
+middleware.unless({ endpoints: [
+  '/login', // if string is passed, the GET method is inferred
+  {
+    methods: ['DELETE', 'POST', '...'],
+    url: '/task/:id/*'
+  }
+]})
+```

index.js

@@ -0,0 +1,68 @@
+const op = () => true
+
+module.exports = function (routerOpts = {}, routerFactory) {
+  routerOpts.defaultRoute = () => false
+  routerFactory = routerFactory || require('find-my-way')
+
+  function exec (options, isIff = true) {
+    const middleware = this
+
+    // independent router instance per config
+    const router = routerFactory(routerOpts)
+
+    const opts = typeof options === 'function' ? { custom: options } : (Array.isArray(options) ? { endpoints: options } : options)
+    if (opts.endpoints && opts.endpoints.length) {
+      // setup matching router
+      opts.endpoints.map(endpoint => typeof endpoint === 'string' ? { methods: ['GET'], url: endpoint } : endpoint).forEach(({ methods, url }) => {
+        router.on(methods, url, op)
+      })
+    }
+
+    const result = function (req, res, next) {
+      // supporting custom matching function
+      if (opts.custom) {
+        if (opts.custom(req)) {
+          if (isIff) {
+            return middleware(req, res, next)
+          }
+        } else if (!isIff) {
+          return middleware(req, res, next)
+        }
+
+        // leave here and do not process opts.endpoints
+        return next()
+      }
+
+      // matching endpoints and moving forward
+      if (router.lookup(req, res)) {
+        if (isIff) {
+          return middleware(req, res, next)
+        }
+      } else if (!isIff) {
+        return middleware(req, res, next)
+      }
+
+      return next()
+    }
+
+    // allowing chaining
+    result.iff = iff
+    result.unless = unless
+
+    return result
+  }
+
+  function iff (options) {
+    return exec.call(this, options, true)
+  }
+  function unless (options) {
+    return exec.call(this, options, false)
+  }
+
+  return function (middleware) {
+    middleware.iff = iff
+    middleware.unless = unless
+
+    return middleware
+  }
+}