doc: add SharedArrayBuffer to Buffer documentation

PR-URL: #15489
Reviewed-By: Joyee Cheung <joyeec9h3@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
Reviewed-By: Michaël Zasso <targos@protonmail.com>

Author: ThomasdenH

doc/api/buffer.md

@@ -66,8 +66,8 @@ differently based on what arguments are provided:
   memory.
 * Passing a string, array, or `Buffer` as the first argument copies the
   passed object's data into the `Buffer`.
-* Passing an [`ArrayBuffer`] returns a `Buffer` that shares allocated memory with
-  the given [`ArrayBuffer`].
+* Passing an [`ArrayBuffer`] or a [`SharedArrayBuffer`] returns a `Buffer` that
+  shares allocated memory with the given array buffer.
 
 Because the behavior of `new Buffer()` changes significantly based on the type
 of value passed as the first argument, applications that do not properly
@@ -361,16 +361,16 @@ changes:
 > [`Buffer.from(arrayBuffer[, byteOffset [, length]])`][`Buffer.from(arrayBuffer)`]
 > instead.
 
-* `arrayBuffer` {ArrayBuffer} An [`ArrayBuffer`] or the `.buffer` property of a
-  [`TypedArray`].
+* `arrayBuffer` {ArrayBuffer|SharedArrayBuffer} An [`ArrayBuffer`],
+  [`SharedArrayBuffer`] or the `.buffer` property of a [`TypedArray`].
 * `byteOffset` {integer} Index of first byte to expose. **Default:** `0`
 * `length` {integer} Number of bytes to expose.
   **Default:** `arrayBuffer.length - byteOffset`
 
-This creates a view of the [`ArrayBuffer`] without copying the underlying
-memory. For example, when passed a reference to the `.buffer` property of a
-[`TypedArray`] instance, the newly created `Buffer` will share the same
-allocated memory as the [`TypedArray`].
+This creates a view of the [`ArrayBuffer`] or [`SharedArrayBuffer`] without
+copying the underlying memory. For example, when passed a reference to the
+`.buffer` property of a [`TypedArray`] instance, the newly created `Buffer` will
+share the same allocated memory as the [`TypedArray`].
 
 The optional `byteOffset` and `length` arguments specify a memory range within
 the `arrayBuffer` that will be shared by the `Buffer`.
@@ -684,8 +684,8 @@ changes:
                  or `ArrayBuffer`.
 -->
 
-* `string` {string|Buffer|TypedArray|DataView|ArrayBuffer} A value to
-  calculate the length of.
+* `string` {string|Buffer|TypedArray|DataView|ArrayBuffer|SharedArrayBuffer} A
+  value to calculate the length of.
 * `encoding` {string} If `string` is a string, this is its encoding.
   **Default:** `'utf8'`
 * Returns: {integer} The number of bytes contained within `string`.
@@ -708,8 +708,8 @@ console.log(`${str}: ${str.length} characters, ` +
             `${Buffer.byteLength(str, 'utf8')} bytes`);
 ```
 
-When `string` is a `Buffer`/[`DataView`]/[`TypedArray`]/[`ArrayBuffer`], the
-actual byte length is returned.
+When `string` is a `Buffer`/[`DataView`]/[`TypedArray`]/[`ArrayBuffer`]/
+[`SharedArrayBuffer`], the actual byte length is returned.
 
 ### Class Method: Buffer.compare(buf1, buf2)
 <!-- YAML
@@ -812,8 +812,8 @@ A `TypeError` will be thrown if `array` is not an `Array`.
 added: v5.10.0
 -->
 
-* `arrayBuffer` {ArrayBuffer} An [`ArrayBuffer`] or the `.buffer` property of a
-  [`TypedArray`].
+* `arrayBuffer` {ArrayBuffer|SharedArrayBuffer} An [`ArrayBuffer`],
+  [`SharedArrayBuffer`], or the `.buffer` property of a [`TypedArray`].
 * `byteOffset` {integer} Index of first byte to expose. **Default:** `0`
 * `length` {integer} Number of bytes to expose.
   **Default:** `arrayBuffer.length - byteOffset`
@@ -857,7 +857,8 @@ const buf = Buffer.from(ab, 0, 2);
 console.log(buf.length);
 ```
 
-A `TypeError` will be thrown if `arrayBuffer` is not an [`ArrayBuffer`].
+A `TypeError` will be thrown if `arrayBuffer` is not an [`ArrayBuffer`] or a
+[`SharedArrayBuffer`].
 
 ### Class Method: Buffer.from(buffer)
 <!-- YAML
@@ -2730,6 +2731,7 @@ This value may depend on the JS engine that is being used.
 [`DataView`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/DataView
 [`JSON.stringify()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify
 [`RangeError`]: errors.html#errors_class_rangeerror
+[`SharedArrayBuffer`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SharedArrayBuffer
 [`String#indexOf()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/indexOf
 [`String#lastIndexOf()`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/lastIndexOf
 [`String.prototype.length`]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/length