koa-tree-router
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A high performance koa router
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Markdown
# Koa tree router
[](https://github.com/steambap/koa-tree-router/actions?workflow=CI)
[](https://npm.im/koa-tree-router)
Koa tree router is a high performance router for Koa.
## Features
- Fast. Up to 11 times faster than Koa-router. [Benchmark](https://github.com/delvedor/router-benchmark)
- Express-style routing using `router.get`, `router.put`, `router.post`, etc.
- Support for `405 method not allowed`
- Multiple middleware per route
## How does it work?
The router relies on a tree structure which makes heavy use of *common prefixes*, it is basically a *compact* [*prefix tree*](https://en.wikipedia.org/wiki/Trie) (or just [*Radix tree*](https://en.wikipedia.org/wiki/Radix_tree)).
This module's tree implementation is based on [julienschmidt/httprouter](https://github.com/julienschmidt/httprouter).
## Installation
```sh
# npm
npm i koa-tree-router
# yarn
yarn add koa-tree-router
```
## Usage
```JS
const Koa = require("koa");
const Router = require("koa-tree-router");
const app = new Koa();
const router = new Router();
router.get("/", function(ctx) {
ctx.body = "hello, world";
});
app.use(router.routes());
app.listen(8080);
```
## API
#### Router([options])
Instance a new router.
```js
const router = require('koa-tree-router')({
onMethodNotAllowed(ctx){
ctx.body = "not allowed"
},
ignoreTrailingSlash: true
})
```
#### on(method, path, middleware)
Register a new route.
```js
router.on('GET', '/example', (ctx) => {
// your code
})
```
#### Shorthand methods
If you want to get expressive, here is what you can do:
```js
router.get(path, middleware)
router.delete(path, middleware)
router.head(path, middleware)
router.patch(path, middleware)
router.post(path, middleware)
router.put(path, middleware)
router.options(path, middleware)
router.trace(path, middleware)
router.connect(path, middleware)
```
If you need a route that supports *all* methods you can use the `all` api.
```js
router.all(path, middleware)
```
#### use(middleware)
You can add middleware that is added to all future routes:
```js
router.use(authMiddleware);
router.get("/foo", (ctx) => { /* your code */ });
router.get("/bar", (ctx) => { /* your code */ });
router.get("/baz", (ctx) => { /* your code */ });
```
This is equivalent to:
```js
router.get("/foo", authMiddleware, (ctx) => { /* your code */ });
router.get("/bar", authMiddleware, (ctx) => { /* your code */ });
router.get("/baz", authMiddleware, (ctx) => { /* your code */ });
```
**Caveat**: `use` must be called before register a new handler. It does not append handlers to registered routes.
#### routes
Returns router middleware.
```JS
app.use(router.routes());
```
#### nested routes
A way to create groups of routes without incuring any per-request overhead.
```JS
const Koa = require("koa");
const Router = require("koa-tree-router");
const app = new Koa();
const router = new Router();
const group = router.newGroup("/foo");
// add a handler for /foo/bar
group.get("/bar", function(ctx) {
ctx.body = "hello, world";
});
app.use(router.routes());
app.listen(8080);
```
Middleware added with `use()` are also added to the nested routes.
#### ctx.params
This object contains key-value pairs of named route parameters.
```JS
router.get("/user/:name", function() {
// your code
});
// GET /user/1
ctx.params.name
// => "1"
```
## How to write routes
There are 3 types of routes:
1.Static
```
Pattern: /static
/static match
/anything-else no match
```
2.Named
Named parameters have the form `:name` and only match a single path segment:
```
Pattern: /user/:user
/user/gordon match
/user/you match
/user/gordon/profile no match
/user/ no match
```
3.Catch-all
Catch-all parameters have the form `*name` and match everything. They must always be at the **end** of the pattern:
```
Pattern: /src/*filepath
/src/ match
/src/somefile.go match
/src/subdir/somefile.go match
```
## Typescript Support
This package has its own declaration files in NPM package, you don't have to do anything extra.
## License
[MIT](LICENSE)