doc: remove IPC channel implementation details

IPC messages are more complicated than a simple pipe passing JSON
objects separated by new line. This removes inaccurate notes about
implementation from the documentation.

PR-URL: #17460
Fixes: #16491
Fixes: #17405
Reviewed-By: Jon Moss <me@jonathanmoss.me>
Reviewed-By: Rich Trott <rtrott@gmail.com>
Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>

doc/api/child_process.md

@@ -366,8 +366,7 @@ By default, `child_process.fork()` will spawn new Node.js instances using the
 
 Node.js processes launched with a custom `execPath` will communicate with the
 parent process using the file descriptor (fd) identified using the
-environment variable `NODE_CHANNEL_FD` on the child process. The input and
-output on this fd is expected to be line delimited JSON objects.
+environment variable `NODE_CHANNEL_FD` on the child process.
 
 *Note*: Unlike the fork(2) POSIX system call, `child_process.fork()` does
 not clone the current process.
@@ -609,9 +608,7 @@ pipes between the parent and child. The value is one of the following:
 2. `'ipc'` - Create an IPC channel for passing messages/file descriptors
    between parent and child. A [`ChildProcess`][] may have at most *one* IPC stdio
    file descriptor. Setting this option enables the [`subprocess.send()`][]
-   method. If the child writes JSON messages to this file descriptor, the
-   [`subprocess.on('message')`][`'message'`] event handler will be triggered in
-   the parent. If the child is a Node.js process, the presence of an IPC channel
+   method. If the child is a Node.js process, the presence of an IPC channel
    will enable [`process.send()`][], [`process.disconnect()`][],
    [`process.on('disconnect')`][], and [`process.on('message')`] within the
    child.
@@ -933,9 +930,8 @@ added: v0.5.9
 The `'message'` event is triggered when a child process uses [`process.send()`][]
 to send messages.
 
-*Note*: The message goes through JSON serialization and parsing. The resulting
-message might not be the same as what is originally sent. See notes in
-[the `JSON.stringify()` specification][`JSON.stringify` spec].
+*Note*: The message goes through serialization and parsing. The resulting
+message might not be the same as what is originally sent.
 
 ### subprocess.channel
 <!-- YAML
@@ -1097,9 +1093,8 @@ be used to send messages to the child process. When the child process is a
 Node.js instance, these messages can be received via the
 [`process.on('message')`][] event.
 
-*Note*: The message goes through JSON serialization and parsing. The resulting
-message might not be the same as what is originally sent. See notes in
-[the `JSON.stringify()` specification][`JSON.stringify` spec].
+*Note*: The message goes through serialization and parsing. The resulting
+message might not be the same as what is originally sent.
 
 For example, in the parent script:
 
@@ -1369,7 +1364,6 @@ unavailable.
 [`ChildProcess`]: #child_process_child_process
 [`Error`]: errors.html#errors_class_error
 [`EventEmitter`]: events.html#events_class_eventemitter
-[`JSON.stringify` spec]: https://tc39.github.io/ecma262/#sec-json.stringify
 [`subprocess.connected`]: #child_process_subprocess_connected
 [`subprocess.disconnect()`]: #child_process_subprocess_disconnect
 [`subprocess.kill()`]: #child_process_subprocess_kill_signal

doc/api/process.md

@@ -94,9 +94,8 @@ The listener callback is invoked with the following arguments:
 * `sendHandle` {Handle object} a [`net.Socket`][] or [`net.Server`][] object, or
   undefined.
 
-*Note*: The message goes through JSON serialization and parsing. The resulting
-message might not be the same as what is originally sent. See notes in
-[the `JSON.stringify()` specification][`JSON.stringify` spec].
+*Note*: The message goes through serialization and parsing. The resulting
+message might not be the same as what is originally sent.
 
 ### Event: 'rejectionHandled'
 <!-- YAML
@@ -1519,9 +1518,8 @@ used to send messages to the parent process. Messages will be received as a
 If Node.js was not spawned with an IPC channel, `process.send()` will be
 `undefined`.
 
-*Note*: The message goes through JSON serialization and parsing. The resulting
-message might not be the same as what is originally sent. See notes in
-[the `JSON.stringify()` specification][`JSON.stringify` spec].
+*Note*: The message goes through serialization and parsing. The resulting
+message might not be the same as what is originally sent.
 
 ## process.setegid(id)
 <!-- YAML
@@ -1951,7 +1949,6 @@ cases:
 [`ChildProcess`]: child_process.html#child_process_class_childprocess
 [`Error`]: errors.html#errors_class_error
 [`EventEmitter`]: events.html#events_class_eventemitter
-[`JSON.stringify` spec]: https://tc39.github.io/ecma262/#sec-json.stringify
 [`console.error()`]: console.html#console_console_error_data_args
 [`console.log()`]: console.html#console_console_log_data_args
 [`domain`]: domain.html