initial commit

router.js

@@ -0,0 +1,121 @@
+/**
+ * Helper functions that when passed a request will return a
+ * boolean indicating if the request uses that HTTP method,
+ * header, host or referrer.
+ */
+const Method = method => req =>
+    req.method.toLowerCase() === method.toLowerCase()
+const Connect = Method('connect')
+const Delete = Method('delete')
+const Get = Method('get')
+const Head = Method('head')
+const Options = Method('options')
+const Patch = Method('patch')
+const Post = Method('post')
+const Put = Method('put')
+const Trace = Method('trace')
+
+const Header = (header, val) => req => req.headers.get(header) === val
+const Host = host => Header('host', host.toLowerCase())
+const Referrer = host => Header('referrer', host.toLowerCase())
+
+const Path = regExp => req => {
+    const url = new URL(req.url)
+    const path = url.pathname
+    const match = path.match(regExp) || []
+    return match[0] === path
+}
+
+/**
+ * The Router handles determines which handler is matched given the
+ * conditions present for each request.
+ */
+class Router {
+    constructor() {
+        this.routes = []
+    }
+
+    handle(conditions, handler) {
+        this.routes.push({
+            conditions,
+            handler,
+        })
+        return this
+    }
+
+    connect(url, handler) {
+        return this.handle([Connect, Path(url)], handler)
+    }
+
+    delete(url, handler) {
+        return this.handle([Delete, Path(url)], handler)
+    }
+
+    get(url, handler) {
+        return this.handle([Get, Path(url)], handler)
+    }
+
+    head(url, handler) {
+        return this.handle([Head, Path(url)], handler)
+    }
+
+    options(url, handler) {
+        return this.handle([Options, Path(url)], handler)
+    }
+
+    patch(url, handler) {
+        return this.handle([Patch, Path(url)], handler)
+    }
+
+    post(url, handler) {
+        return this.handle([Post, Path(url)], handler)
+    }
+
+    put(url, handler) {
+        return this.handle([Put, Path(url)], handler)
+    }
+
+    trace(url, handler) {
+        return this.handle([Trace, Path(url)], handler)
+    }
+
+    all(handler) {
+        return this.handle([], handler)
+    }
+
+    route(req) {
+        const route = this.resolve(req)
+
+        if (route) {
+            return route.handler(req)
+        }
+
+        return new Response('resource not found', {
+            status: 404,
+            statusText: 'not found',
+            headers: {
+                'content-type': 'text/plain',
+            },
+        })
+    }
+
+    /**
+     * resolve returns the matching route for a request that returns
+     * true for all conditions (if any).
+     */
+    resolve(req) {
+        return this.routes.find(r => {
+            if (!r.conditions || (Array.isArray(r) && !r.conditions.length)) {
+                return true
+            }
+
+            if (typeof r.conditions === 'function') {
+                return r.conditions(req)
+            }
+
+            return r.conditions.every(c => c(req))
+        })
+    }
+}
+
+module.exports = Router