Problem with E.toString #4594

espruino-discuss · 2025-02-12T13:08:38Z

espruino-discuss
Feb 12, 2025
Maintainer

Posted at 2018-01-26 by ClearMemory041063

Here is the test code

//xtest.js 26 Jan2018
// trying this on a Pico
//try changing the value of chk

var n =100, chk=23*1024;
var tdata=new Uint8Array(chk);
var i;
for(i=0;i<1024;i++){
  tdata[i]=0x30;
  tdata[i+1024]=0x31;
}//next i

function xsend(a){console.log(n,a.length);}

function test(){
while (n){
  xsend(E.toString(tdata));
  n--;
}
}//end test


test();

Here is the output

 1v95 Copyright 2017 G.Williams
>100 23552
99 23552
98 23552
97 23552
Uncaught Error: Field or method "length" does not already exist, and can't create it on undefined
 at line 13 col 16
console.log(n,a.length);
               ^
in function "xsend" called from line 17 col 26
  xsend(E.toString(tdata));
                         ^
in function "test" called from line 1 col 6
test();
     ^
=undefined
>

Similar problem on ESP8266 running Espruino, but different array sizes to get it to run at all.

espruino-discuss · 2025-02-12T13:08:41Z

espruino-discuss
Feb 12, 2025
Maintainer Author

Posted at 2018-01-27 by ClearMemory041063

Trying process.memory to attempt a debug

//xtest2.js 27 Jan2018
// trying this on a Pico
//try changing the value of chk

// process.memory uncommented =PM
// comment out process.memory =NPM
///
// chk=1*1024 works both cases
// chk =2*1024 works with PM,fails NPM
// chk=25*1024 works with PM, fails NPM
// chk=26*1024 fails just too big
var n =100, chk=25*1024; 
var tdata=new Uint8Array(chk);

function xsend(a){
  console.log(n,a.length);
//  process.memory();// this makes it work
}//end xsend

function test(){
var a;
while (n){
  xsend(E.toString(tdata)); //fails if no process.memory
  n--;
}
}//end test

setTimeout(function () {
 test();
}, 1000);

The process.memory() fixes the bug.

 1v95 Copyright 2017 G.Williams
>
=undefined
100 25600
99 25600
98 25600
97 25600
Uncaught Error: Field or method "length" does not already exist, and can't create it on undefined
 at line 16 col 16
console.log(n,a.length);
               ^
in function "xsend" called from line 23 col 26
  xsend(E.toString(tdata)); //fails if no process.memory
                         ^
in function "test" called from line 1 col 6
test();
     ^
in function called from system
>

Posted at 2018-01-27 by Wilberforce

You are creating a 23k string. That is quite large in espruino world!

The esp8266'has even less resources, so try changing the 23 to 4 and see if it works!

Posted at 2018-01-27 by ClearMemory041063

The example above is on a Pico.
It is an attempt to zero in on the bug first found in the following code.

For the ESP8266 -01 try this code

//WSDesp8266A/js 27Jan2018
// using process.memory to fix bug

//http//192.168.1.6:8080
//ESP8266 with Espruino flahed


// list of Wifi and passwords
var SSID="ssid";
var key="keykey";
var Startagain=0;
var myinterval;

var n =100, chk=2*1024;
var tdata=new Uint8Array(chk);
var i;
for(i=0;i<1024;i++){
  tdata[i]=0x30;
  tdata[i+1024]=0x31;
}//next i

var page = 
"<html>\r\n<body>\r\n<textarea id=\"demo\" rows=\"32\" cols=\"64\"></textarea>\r\n<script>\r\nvar ws;\r\nvar data=\"\";\r\n//setTimeout(function(){\r\nws = new WebSocket(\"ws://\" + location.host + \"/my_websocket\", \"protocolOne\");\r\nws.onmessage = function (event) { \r\ndata+=event.data;\r\ndocument.getElementById(\"demo\").innerHTML = data.length;\r\nws.send(\"Hello to Espruino!\"); \r\n };\r\n//setTimeout(function() { ws.send(\"Hello to Espruino!\"); }, //1000);}\r\n//,1000);\r\n\r\n</script></body>\r\n</html>\r\n"
;
function onPageRequest(req, res) {
  res.writeHead(200, {'Content-Type': 'text/html'});
  res.end(page);
}

function test(){

console.log("Start connection process");
var wifi = require("Wifi");
 console.log("Try Connecting to WiFi ",SSID);
 wifi.connect(SSID,{password:key}, function(err) {
  console.log(err);
   if (err){Startagain=1;return;
}
 console.log("connected? err=", err, "info=", wifi.getIP());
     console.log("Wi-Fi Connected");
     clearInterval( myinterval);
     var t=getTime();
var server = require('ws').createServer(onPageRequest);
server.listen(8080);
server.on("websocket", function(ws) {
    ws.on('message',function(msg) {
    n--;
  print("n=",n,"t:",(getTime()-t).toFixed(3),"sec");
      print("[WS] "+JSON.stringify(msg));
      if(n){
        ws.send(E.toString(tdata));
        process.memory();
      }
    });
  t=getTime();
  ws.send(E.toString(tdata));
  process.memory();
  print("n=",n,"t:",(getTime()-t).toFixed(3),"sec");
});
 });//end connect
}//end test

myinterval=setInterval(function () {
  console.log("Test for error");
  if(Startagain){
   Startagain=0;
   test();
  }//end of Startagain
}, 2000);

test();

Posted at 2018-01-29 by @gfwilliams

The issue you're hitting here is actually one of fragmentation. The standard Flat String allocator tries to allocate a flat string quickly - and if the free list (not the actual data!) gets fragmented it can fail.

I've now changed E.toString to try harder (which fixes your problem) but have also made is pass through Uint8Arrays if they're backed by a flat string - so in that case it'll make things much faster for you as well.

Posted at 2018-01-29 by ClearMemory041063

Thanks!

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Espruino JavaScript

Problem with E.toString #4594

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espruino-discuss Feb 12, 2025 Maintainer

Here is the test code

Here is the output

Replies: 1 comment

Uh oh!

espruino-discuss Feb 12, 2025 Maintainer Author

Trying process.memory to attempt a debug

espruino-discuss
Feb 12, 2025
Maintainer

espruino-discuss
Feb 12, 2025
Maintainer Author