This PR aims at replacing next-server/lib/event-emitter.js by mitt.
Fix https://github.com/zeit/next.js/issues/4908
event-emitter.js is ~400 bytes gzipped vs mitt is 200 bytes
Extends on #5927, instead of `.default` we'll expose `.render` which is semantically more correct / mirrors the naming of the custom server API.
I've updated the spec in #5927 to reflect this change.
(copied from #5927):
```js
const http = require('http')
const page = require('./.next/serverless/about.js')
const server = new http.Server((req, res) => page.render(req, res))
server.listen(3000, () => console.log('Listening on http://localhost:3000'))
```
The current reasonml needs an example of how to do getInitialProps. tmepple posted the only known way of doing it in [this comment](https://github.com/zeit/next.js/issues/4202#issuecomment-439175214). It is unlikely reasonml users are going to discover that comment or figure it out on their own so having it in an example is critical.
Also, dependencies updated. After updating dependencies, I get this error:
```
ModuleBuildError: Module build failed (from ./node_modules/next/dist/build/webpack/loaders/next-babel-loader.js):
[1] Error: Cannot find module '@babel/core'
[1] babel-loader@8 requires Babel 7.x (the package '@babel/core'). If you'd like to use Babel 6.x ('babel-core'), you should install 'babel-loader@7'.
```
Seems like @babel/core is required as peer dependency per [this comment](https://github.com/babel/gulp-babel/issues/124#issuecomment-326853222) so I added it.
The way to do getInitialProps has changed in 7.0.2 canary so this also has a comment in the code about what change is required to get that working.
Saw a reply on the original pull request that the WebSocket using a random port broke their set up so I added a `--websocket` or `-w` argument similar to the `-p` argument to allow manually setting this port also.
Fixes#5845
Implement tslint for core files
**What is this?**
Implements tslint for both next and next-server, but keeps standardjs/eslint for the .js files that are still there, we're gradually migrating to Typescript.
**How does it work?**
Before every commit (pre-commit) we execute the following `tslint` command:
`tslint -c tslint.json 'packages/**/*.ts`
**TSLint Rules**
In order to avoid as much changes as possible I marked some rules as false. This way we can improve the linter but making sure this step will not break things. (see tslint.json)
**Note**
After merging this PR, you'll need to update your dependencies since it adds tslint to package.json
**This does not change existing behavior.**
building to serverless is completely opt-in.
- Implements `target: 'serverless'` in `next.config.js`
- Removes `next build --lambdas` (was only available on next@canary so far)
This implements the concept of build targets. Currently there will be 2 build targets:
- server (This is the target that already existed / the default, no changes here)
- serverless (New target aimed at compiling pages to serverless handlers)
The serverless target will output a single file per `page` in the `pages` directory:
- `pages/index.js` => `.next/serverless/index.js`
- `pages/about.js` => `.next/serverless/about.js`
So what is inside `.next/serverless/about.js`? All the code needed to render that specific page. It has the Node.js `http.Server` request handler function signature:
```ts
(req: http.IncomingMessage, res: http.ServerResponse) => void
```
So how do you use it? Generally you **don't** want to use the below example, but for illustration purposes it's shown how the handler is called using a plain `http.Server`:
```js
const http = require('http')
// Note that `.default` is needed because the exported module is an esmodule
const handler = require('./.next/serverless/about.js').default
const server = new http.Server((req, res) => handler(req, res))
server.listen(3000, () => console.log('Listening on http://localhost:3000'))
```
Generally you'll upload this handler function to an external service like [Now v2](https://zeit.co/now-2), the `@now/next` builder will be updated to reflect these changes. This means that it'll be no longer neccesary for `@now/next` to do some of the guesswork in creating smaller handler functions. As Next.js will output the smallest possible serverless handler function automatically.
The function has 0 dependencies so no node_modules are required to run it, and is generally very small. 45Kb zipped is the baseline, but I'm sure we can make it even smaller in the future.
One important thing to note is that the function won't try to load `next.config.js`, so `publicRuntimeConfig` / `serverRuntimeConfig` are not supported. Reasons are outlined here: #5846
So to summarize:
- every page becomes a serverless function
- the serverless function has 0 dependencies (they're all inlined)
- "just" uses the `req` and `res` coming from Node.js
- opt-in using `target: 'serverless'` in `next.config.js`
- Does not load next.config.js when executing the function
TODO:
- [x] Compile next/dynamic / `import()` into the function file, so that no extra files have to be uploaded.
- [x] Setting `assetPrefix` at build time for serverless target
- [x] Support custom /_app
- [x] Support custom /_document
- [x] Support custom /_error
- [x] Add `next.config.js` property for `target`
Need discussion:
- [ ] Since the serverless target won't support `publicRuntimeConfig` / `serverRuntimeConfig` as they're runtime values. I think we should support build-time env var replacement with webpack.DefinePlugin or similar.
- [ ] Serving static files with the correct cache-control, as there is no static file serving in the serverless target
Explains in details how the "with-universal-configuration" example works and rename it to "with-universal-configuration-build-time". Changing the example name makes the purpose of the example clear.
The "env-config.js" file introduce one more sample of variable usage that instantiates an immediate value of the local environment variable. This makes it even clearer how build-time variable configuration works. The "index.js" page makes explicit the use of these configured environment variables.
The universal configuration confusion happens when the value of the environment variable is used directly in the application causing an effect in server-side but not on the client side.
This example show how you can test Next.js apps with [react-testing-library](https://github.com/kentcdodds/react-testing-library).
This library encourages your applications to be more accessible and allows you to get your tests closer to using your components the way a user will, which allows your tests to give you more confidence that your application will work when a real user uses it. And also, is a replacement for enzyme.
<img width="733" alt="Image showing the words next.js + react testing library" src="https://user-images.githubusercontent.com/4689228/50387208-40223200-06de-11e9-9358-607092eb25a0.png">
This fixes the `with-jest-typescript` example to keep jest in sync with babel-jest (also updated to the latest of both). Having them resolve to different versions was resulting in weird errors.
When attempting to update the `transform` property in `jest.setup.js` to add babel-jest support to *.js/jsx files, it would throw:
> Plugin 0 specified in "node_modules/next/babel.js" provided an invalid property of "default" (While processing preset: "node_modules/next/babel.js")
Indirectly, this will fix https://github.com/zeit/next.js/issues/5917, once the author updates `jest.setup.js` to have:
```js
transform: {
'^.+\\.(js|tsx)?$': 'babel-jest',
},
```
This brings us one step closer to outputting serverless functions as renderToHTML now renders the passed components, which allows us to bundle the renderToHTML function together with statically imported components in webpack.
Resolves#4055
Credit: https://github.com/zeit/next.js/pull/5095
I didn't use the ignore webpack plugin from the original PR and tested bundle size with https://github.com/zeit/next.js/pull/5339 - seems to be safe on that front.
Was able to get tests to pass locally, unsure of what goes wrong in CI 🤷♂️
**Questions**
1) The initial PR didn't include changes to `next-server/lib/router` in `getRouteInfo()`. Should the same changes be made within?
2) Should we add a test for rendering a component created via `forwardRef()`?
`component-with-forwardedRef`:
```javascript
export default React.forwardRef((props, ref) => <span {...props} forwardedRef={ref}>This is a component with a forwarded ref</span>);
```
some test:
```javascript
test('renders from forwardRef', async () => {
const $ = await get$('/component-with-forwardedRef')
const span = $('span')
expect(span.text()).toMatch(/This is a component with a forwarded ref/)
})
```
As I detailed in [this thread on Spectrum](https://spectrum.chat/?t=3df7b1fb-7331-4ca4-af35-d9a8b1cacb2c), the dev experience would be a lot nicer if the server started listening as soon as possible, before the slow initialization steps. That way, instead of manually polling the dev URL until the server's up (this can take a long time!), I can open it right away and the responses will be delivered when the dev server is done initializing.
This makes a few changes to the dev server:
* Move `HotReloader` creation to `prepare`. Ideally, more things (from the non-dev `Server`) would be moved to a later point as well, because creating `next({ ... })` is quite slow.
* In `run`, wait for a promise to resolve before doing anything. This promise automatically gets resolved whenever `prepare` finishes successfully.
And the `next dev` and `next start` scripts:
* Since we want to log that the server is ready/listening before the intensive build process kicks off, we return the app instance from `startServer` and the scripts call `app.prepare()`.
This should all be backwards compatible, including with all existing custom server recommendations that essentially say `app.prepare().then(listen)`. But now, we could make an even better recommendation: start listening right away, then call `app.prepare()` in the `listen` callback. Users would be free to make that change and get better DX.
Try it and I doubt you'll want to go back to the old way. :)
This message is from @timneutkens after making changes:
- Convert executables to Typescript
- Remove `minimist` in favor of `arg`
- Implement `--node-args` usage: `--node-args="--throw-deprecation"`
- Adds tests for usage of the `next` cli
