evdev/index.js

An Evdev events reader.

#!/usr/bin/env node
const EvdevReader = require("./lib");

//var device_streams = new read_device({devices:["/dev/input/by-path/pci-0000:45:00.0-usb-0:1:1.0-event-joystick"]});
const reader = new EvdevReader();

if( !process.argv[2]){
  console.log("No target provided. Matching default \"event-joystick\" devices");
}
const target_match = ((process.argv[2])? process.argv[2]: "event-joystick");

reader.on("EV_KEY",function(data){
  console.log("key : ",data.code,data.value);
}).on("EV_ABS",function(data){
  console.log("Absolute axis : ",data.code,data.value);
}).on("EV_REL",function(data){
  console.log("Relative axis : ",data.code,data.value);
}).on("error",function(e){
  console.log("reader error : ",e);
})

console.log("searching for event streams matching %s in : /dev/input/by-path",  target_match);
reader.search("/dev/input/by-path", target_match, function(err,files){
  var device;
  const target_index =  parseInt(process.argv[3]); // don't forget to check if NaN
  if(err){
    console.log("node-evdev search stream : ", err);
  }else if(files.length == 1){
    console.log("Opening %s", files[0]);
    device = reader.open(files[0]);
  }else if ( 1 < files.length){
    if(Number.isNaN(target_index)){
      console.log("Found %d files : %s", files.length, prettyPrint(files));
      console.log("Provide a third argument \"index\" to choose your file. e.g. :");
      console.log("\t./index.js %s 0", target_match);
      console.log("Or provide a more precise filter to match only 1 device");
      return;
    }else if(!files[target_index]){
      console.error("No file at index %d : %s", target_index, prettyPrint(files));
      return;
    }else{
      console.log("Opening : %s", files[target_index]);
      device = reader.open(files[target_index]);
    }
  }else{
    console.log("No device matching %s found", target_match );
    return;
  }

  //We don't check if device is assigned because any code path that does not return should assign it.
  device.on("open",function(){
    console.log(device.id);
  });
});


function prettyPrint(ar){
  return `[\n\t${ar.join(",\n\t")}\n]`
}