Error "Buffer is not defined" during start Angular application

[p-gatto]

Hi, With Angula17, nodejs v. 20.10 and modbus-serial 8.0.16 I'm trying to carry out readings with the modbus protocol using 'modbus-serial' but I have the following problem when starting the application highlighted in the console:

Uncaught ReferenceError: Buffer is not defined at addBufferBitOp (buffer_bit.js:30:5) at node_modules/modbus-serial/index.js (index.js:20:1) at __require2 (chunk-FWOMF3V2.js?v=883fa305:41:50) at index.js:1194:33

No errors are reported within the buffer_bit.js file at design time. Thanks in advance for clarifications.

Paolo

[yaacov]

Hi, thank you for the issue,

I am adding a help wanted label, so if someone knows the answer they will know to help.

[p-gatto]

Hi, In my opinion the problem lies in not correctly recalling the library resources within the Angular component. Below is the code I wrote:

import { Injectable } from '@angular/core';

@Injectable({ providedIn: 'root' }) export class ModbusService {

constructor() { }

readHoldingRegisters() {

// create an empty modbus client
const ModbusRTU = require("modbus-serial");
const client = new ModbusRTU();

// open connection to a tcp line
client.connectTCP("192.168.1.54", { port: 502 });
client.setID(1);

// read the values of 10 registers starting at address 0
// on device number 1. and log the values to the console.
setInterval(function() {

  console.log('Ciao mondo!!!');
  /* client.readHoldingRegisters(0, 10, function(err, data) {
    console.log(data.data);
  }); */

}, 1000);

}

When I call the "readHoldingRegisters" function I get the following error:

core.mjs:6531 ERROR Error: Dynamic require of "modbus-serial" is not supported at main.js:6:9 at _ModbusService.readHoldingRegisters (modbus.service.ts:13:23) at _HomeComponent.readHR (home.component.ts:18:25) at HomeComponent_Template_button_click_12_listener (home.component.html:8:72) at executeListenerWithErrorHandling (core.mjs:25518:16) at wrapListenerIn_markDirtyAndPreventDefault (core.mjs:25552:22) at HTMLButtonElement. (platform-browser.mjs:749:112) at _ZoneDelegate.invokeTask (zone.js:403:31) at core.mjs:14511:55 at AsyncStackTaggingZoneSpec.onInvokeTask (core.mjs:14511:36) Mostra 1 altro fotogramm

Anche se ho lanciato il seguente comando "npm i --save-dev @types/node" e registrato in tsconfig.ts nei types "node". Thanks in advance for clarifications.

Paolo

[teddy1565]

in my understanding Angular is a frontend develop framework

modbus-serial is a backend library

One of the most obvious possibility questions Frontend not support Buffer, Frontend only have ArrayBuffer it's the biggest difference between front-end and back-end execution environments.

[p-gatto]

Hi Teddy, You're right, I tried to manage it from the back-end and now I can communicate with the slave. Thanks for feedback!

[aaelephant]

in vue too

[FlowerSeaSea]

在我的理解中，Angular 是一个前端开发框架

modbus-serial 是一个后端库

最明显的可能性问题之一：前端不支持 Buffer，前端只有 ArrayBuffer，这是前端和后端执行环境之间最大的区别。

如何转为不同类型的数据，比如float，short, word等，我试图用data.buffer.readFloatBE()转化但是得到的结果不正确，请问该如何正确拿到对应类型的值

[teddy1565]

在我的理解中，Angular 是一个前端开发框架

modbus-serial 是一个后端库

最明显的可能性问题之一：前端不支持 Buffer，前端只有 ArrayBuffer，这是前端和后端执行环境之间最大的区别。

如何转为不同类型的数据，比如float，short, word等，我试图用data.buffer.readFloatBE()转化但是得到的结果不正确，请问该如何正确拿到对应类型的值

Show your code?