JS Documentation (#3535)

* Initial JS documentation
* Spelling fix

Co-authored-by: あく <alleteam@gmail.com>

documentation/js/js_serial.md

@@ -0,0 +1,107 @@
+# js_serial {#js_serial}
+
+# Serial module
+```js
+let serial = require("serial");
+```
+# Methods
+
+## setup
+Configure serial port. Should be called before all other methods.
+
+### Parameters
+- Serial port name (usart, lpuart)
+- Baudrate
+
+### Examples:
+```js
+// Configure LPUART port with baudrate = 115200
+serial.setup("lpuart", 115200);
+```
+
+## write
+Write data to serial port
+
+### Parameters
+One or more arguments of the following types:
+- A string
+- Single number, each number is interpreted as a byte
+- Array of numbers, each number is interpreted as a byte
+- ArrayBuffer or DataView
+
+### Examples:
+```js
+serial.write(0x0a); // Write a single byte 0x0A
+serial.write("Hello, world!"); // Write a string
+serial.write("Hello, world!", [0x0d, 0x0a]); // Write a string followed by two bytes
+```
+
+## read
+Read a fixed number of characters from serial port.
+
+### Parameters
+- Number of bytes to read
+- (optional) Timeout value in ms
+
+### Returns
+A sting of received characters or undefined if nothing was received before timeout.
+
+### Examples:
+```js
+serial.read(1); // Read a single byte, without timeout
+serial.read(10, 5000); // Read 10 bytes, with 5s timeout
+```
+
+## readln
+Read from serial port untill line break character
+
+### Parameters
+(optional) Timeout value in ms
+
+### Returns
+A sting of received characters or undefined if nothing was received before timeout.
+
+### Examples:
+```js
+serial.readln(); // Read without timeout
+serial.readln(5000); // Read with 5s timeout
+```
+
+## readBytes
+Read from serial port untill line break character
+
+### Parameters
+- Number of bytes to read
+- (optional) Timeout value in ms
+
+### Returns
+ArrayBuffer with received data or undefined if nothing was received before timeout.
+
+### Examples:
+```js
+serial.readBytes(4); // Read 4 bytes, without timeout
+
+// Read one byte from receive buffer with zero timeout, returns UNDEFINED if Rx bufer is empty
+serial.readBytes(1, 0);
+```
+
+## expect
+Search for a string pattern in received data stream
+
+### Parameters
+- Single argument or array of the following types:
+    - A string
+    - Array of numbers, each number is interpreted as a byte
+- (optional) Timeout value in ms
+
+### Returns
+Index of matched pattern in input patterns list, undefined if nothing was found.
+
+### Examples:
+```js
+// Wait for root shell prompt with 1s timeout, returns 0 if it was received before timeout, undefined if not
+serial.expect("# ", 1000); 
+
+// Infinitely wait for one of two strings, should return 0 if the first string got matched, 1 if the second one
+serial.expect([": not found", "Usage: "]);
+```