WebSerial Polyfill for Deno

This project provides a polyfill for the Web Serial API in Deno, enabling serial port communication in Deno applications using a familiar web-compatible interface.

Usage

Currently, this project does not ship any pre-built binaries. To use the polyfill, you need to build the native adapter yourself:

1. Clone the repository and navigate to its directory.

2. Build the native binary using Cargo:

   cargo build --release
   
   
   

3. Set the WEB_SERIAL_PATH environment variable to the folder containing the compiled binary (typically target/release):

   export WEB_SERIAL_PATH=/path/to/deno_serial/target/release
   
   
   

4. Use the polyfill in your Deno project as documented.

Make sure you have Rust and Cargo installed.

Example

1. Arduino Blink Sketch

   Upload the following sketch to your Arduino:

   String inputString = "";
   bool stringComplete = false;
   
   void setup() {
       Serial.begin(115200);
       inputString.reserve(200);
   
       pinMode(2, OUTPUT);
   }
   
   void loop() {
       if (!stringComplete) return;
       inputString.trim();
       if (inputString != "OFF" && inputString != "ON") return;
       digitalWrite(2, inputString == "ON");
   
       inputString = "";
       stringComplete = false;
   }
   
   void serialEvent() {
       while (Serial.available()) {
           char inChar = (char)Serial.read();
           inputString += inChar;
           if (inChar == '\n') {
           stringComplete = true;
           }
       }
   }
   
   
   

   Blinking via Web Serial in Deno:

   import "../mod.ts"; // Import the polyfill
   import { delay } from "jsr:@std/async/delay";
   
   // get first available serial port
   const port = await navigator.serial.requestPort();
   await port.open({ baudRate: 115200 });
   
   // read every chunk from the serial port
   port.readable!
       .pipeThrough(new TextDecoderStream())
       .pipeTo(new WritableStream({
           write(chunk) {
               console.log(chunk.trim());
           }
       }));
   
   // blink fast
   const writer = port.writable!.getWriter();
   
   while (true) {
       await writer.write(new TextEncoder().encode("ON\n"));
       await delay(100);
       await writer.write(new TextEncoder().encode("OFF\n"));
       await delay(100);
   }
   
   
   

License

Apache-2.0. Check LICENSE for more information.