docs: add IPC doc (#32059)

* docs: add IPC doc

* fix: use "string" primitive

* use 'string' ipcrenderer

* use "number" primitive

* Update docs/tutorial/ipc.md

Co-authored-by: Jeremy Rose <nornagon@nornagon.net>

* Update docs/tutorial/ipc.md

Co-authored-by: Jeremy Rose <nornagon@nornagon.net>

* add code sample

Co-authored-by: Jeremy Rose <nornagon@nornagon.net>

docs/api/ipc-main.md

@@ -1,3 +1,10 @@
+---
+title: "ipcMain"
+description: "Communicate asynchronously from the main process to renderer processes."
+slug: ipc-main
+hide_title: false
+---
+
 # ipcMain
 
 > Communicate asynchronously from the main process to renderer processes.
@@ -9,7 +16,9 @@ process, it handles asynchronous and synchronous messages sent from a renderer
 process (web page). Messages sent from a renderer will be emitted to this
 module.
 
-## Sending Messages
+For usage examples, check out the [IPC tutorial].
+
+## Sending messages
 
 It is also possible to send messages from the main process to the renderer
 process, see [webContents.send][web-contents-send] for more information.
@@ -21,36 +30,6 @@ process, see [webContents.send][web-contents-send] for more information.
   coming from frames that aren't the main frame (e.g. iframes) whereas
   `event.sender.send(...)` will always send to the main frame.
 
-An example of sending and handling messages between the render and main
-processes:
-
-```javascript
-// In main process.
-const { ipcMain } = require('electron')
-ipcMain.on('asynchronous-message', (event, arg) => {
-  console.log(arg) // prints "ping"
-  event.reply('asynchronous-reply', 'pong')
-})
-
-ipcMain.on('synchronous-message', (event, arg) => {
-  console.log(arg) // prints "ping"
-  event.returnValue = 'pong'
-})
-```
-
-```javascript
-// In renderer process (web page).
-// NB. Electron APIs are only accessible from preload, unless contextIsolation is disabled.
-// See https://www.electronjs.org/docs/tutorial/process-model#preload-scripts for more details.
-const { ipcRenderer } = require('electron')
-console.log(ipcRenderer.sendSync('synchronous-message', 'ping')) // prints "pong"
-
-ipcRenderer.on('asynchronous-reply', (event, arg) => {
-  console.log(arg) // prints "pong"
-})
-ipcRenderer.send('asynchronous-message', 'ping')
-```
-
 ## Methods
 
 The `ipcMain` module has the following method to listen for events:
@@ -59,7 +38,7 @@ The `ipcMain` module has the following method to listen for events:
 
 * `channel` string
 * `listener` Function
-  * `event` IpcMainEvent
+  * `event` [IpcMainEvent][ipc-main-event]
   * `...args` any[]
 
 Listens to `channel`, when a new message arrives `listener` would be called with
@@ -69,7 +48,7 @@ Listens to `channel`, when a new message arrives `listener` would be called with
 
 * `channel` string
 * `listener` Function
-  * `event` IpcMainEvent
+  * `event` [IpcMainEvent][ipc-main-event]
   * `...args` any[]
 
 Adds a one time `listener` function for the event. This `listener` is invoked
@@ -93,8 +72,8 @@ Removes listeners of the specified `channel`.
 ### `ipcMain.handle(channel, listener)`
 
 * `channel` string
-* `listener` Function<Promise\<void> | any>
-  * `event` IpcMainInvokeEvent
+* `listener` Function<Promise\<void&#62; | any&#62;
+  * `event` [IpcMainInvokeEvent][ipc-main-invoke-event]
   * `...args` any[]
 
 Adds a handler for an `invoke`able IPC. This handler will be called whenever a
@@ -104,14 +83,14 @@ If `listener` returns a Promise, the eventual result of the promise will be
 returned as a reply to the remote caller. Otherwise, the return value of the
 listener will be used as the value of the reply.
 
-```js
-// Main process
+```js title='Main Process'
 ipcMain.handle('my-invokable-ipc', async (event, ...args) => {
   const result = await somePromise(...args)
   return result
 })
+```
 
-// Renderer process
+```js title='Renderer Process'
 async () => {
   const result = await ipcRenderer.invoke('my-invokable-ipc', arg1, arg2)
   // ...
@@ -130,7 +109,7 @@ provided to the renderer process. Please refer to
 ### `ipcMain.handleOnce(channel, listener)`
 
 * `channel` string
-* `listener` Function<Promise\<void> | any>
+* `listener` Function<Promise\<void&#62; | any&#62;
   * `event` IpcMainInvokeEvent
   * `...args` any[]
 
@@ -146,13 +125,16 @@ Removes any handler for `channel`, if present.
 ## IpcMainEvent object
 
 The documentation for the `event` object passed to the `callback` can be found
-in the [`ipc-main-event`](structures/ipc-main-event.md) structure docs.
+in the [`ipc-main-event`][ipc-main-event] structure docs.
 
 ## IpcMainInvokeEvent object
 
 The documentation for the `event` object passed to `handle` callbacks can be
-found in the [`ipc-main-invoke-event`](structures/ipc-main-invoke-event.md)
+found in the [`ipc-main-invoke-event`][ipc-main-invoke-event]
 structure docs.
 
+[IPC tutorial]: ../tutorial/ipc.md
 [event-emitter]: https://nodejs.org/api/events.html#events_class_eventemitter
-[web-contents-send]: web-contents.md#contentssendchannel-args
+[web-contents-send]: ../api/web-contents.md#contentssendchannel-args
+[ipc-main-event]:../api/structures/ipc-main-event.md
+[ipc-main-invoke-event]:../api/structures/ipc-main-invoke-event.md

docs/api/ipc-renderer.md

@@ -1,3 +1,10 @@
+---
+title: "ipcRenderer"
+description: "Communicate asynchronously from a renderer process to the main process."
+slug: ipc-renderer
+hide_title: false
+---
+
 # ipcRenderer
 
 > Communicate asynchronously from a renderer process to the main process.
@@ -9,7 +16,7 @@ methods so you can send synchronous and asynchronous messages from the render
 process (web page) to the main process. You can also receive replies from the
 main process.
 
-See [ipcMain](ipc-main.md) for code examples.
+See [IPC tutorial](../tutorial/ipc.md) for code examples.
 
 ## Methods
 
@@ -70,7 +77,7 @@ throw an exception.
 > them. Attempting to send such objects over IPC will result in an error.
 
 The main process handles it by listening for `channel` with the
-[`ipcMain`](ipc-main.md) module.
+[`ipcMain`](./ipc-main.md) module.
 
 If you need to transfer a [`MessagePort`][] to the main process, use [`ipcRenderer.postMessage`](#ipcrendererpostmessagechannel-message-transfer).
 
@@ -98,7 +105,7 @@ throw an exception.
 > them. Attempting to send such objects over IPC will result in an error.
 
 The main process should listen for `channel` with
-[`ipcMain.handle()`](ipc-main.md#ipcmainhandlechannel-listener).
+[`ipcMain.handle()`](./ipc-main.md#ipcmainhandlechannel-listener).
 
 For example:
 
@@ -124,11 +131,11 @@ If you do not need a response to the message, consider using [`ipcRenderer.send`
 * `channel` string
 * `...args` any[]
 
-Returns `any` - The value sent back by the [`ipcMain`](ipc-main.md) handler.
+Returns `any` - The value sent back by the [`ipcMain`](./ipc-main.md) handler.
 
 Send a message to the main process via `channel` and expect a result
 synchronously. Arguments will be serialized with the [Structured Clone
-Algorithm][SCA], just like [`window.postMessage`][], so prototype chains will not be
+Algorithm][SCA], just like [`window.postMessage`], so prototype chains will not be
 included. Sending Functions, Promises, Symbols, WeakMaps, or WeakSets will
 throw an exception.
 
@@ -140,13 +147,13 @@ throw an exception.
 > Electron's IPC to the main process, as the main process would have no way to decode
 > them. Attempting to send such objects over IPC will result in an error.
 
-The main process handles it by listening for `channel` with [`ipcMain`](ipc-main.md) module,
+The main process handles it by listening for `channel` with [`ipcMain`](./ipc-main.md) module,
 and replies by setting `event.returnValue`.
 
 > :warning: **WARNING**: Sending a synchronous message will block the whole
 > renderer process until the reply is received, so use this method only as a
 > last resort. It's much better to use the asynchronous version,
-> [`invoke()`](ipc-renderer.md#ipcrendererinvokechannel-args).
+> [`invoke()`](./ipc-renderer.md#ipcrendererinvokechannel-args).
 
 ### `ipcRenderer.postMessage(channel, message, [transfer])`
 
@@ -158,7 +165,7 @@ Send a message to the main process, optionally transferring ownership of zero
 or more [`MessagePort`][] objects.
 
 The transferred `MessagePort` objects will be available in the main process as
-[`MessagePortMain`](message-port-main.md) objects by accessing the `ports`
+[`MessagePortMain`](./message-port-main.md) objects by accessing the `ports`
 property of the emitted event.
 
 For example:
@@ -197,7 +204,7 @@ the host page instead of the main process.
 ## Event object
 
 The documentation for the `event` object passed to the `callback` can be found
-in the [`ipc-renderer-event`](structures/ipc-renderer-event.md) structure docs.
+in the [`ipc-renderer-event`](./structures/ipc-renderer-event.md) structure docs.
 
 [event-emitter]: https://nodejs.org/api/events.html#events_class_eventemitter
 [SCA]: https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API/Structured_clone_algorithm

docs/fiddles/ipc/pattern-1/index.html

@@ -0,0 +1,14 @@
+<!DOCTYPE html>
+<html>
+  <head>
+    <meta charset="UTF-8">
+    <!-- https://developer.mozilla.org/en-US/docs/Web/HTTP/CSP -->
+    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self'">
+    <title>Hello World!</title>
+  </head>
+  <body>
+    Title: <input id="title"/>
+    <button id="btn" type="button">Set</button>
+    <script src="./renderer.js"></script>
+  </body>
+</html>