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问如何使用ESCPOS API模块在Nodejs中动态生成表行
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Stack Overflow用户

提问于 2019-08-14 15:42:18

回答 2查看 743关注 0票数 0

几天前，我正在努力使用ESCPOS Java API打印收据，但失败了，因为我找不到一个足够简单的USB API来允许该程序使用USB接口打印到我的热敏打印机上。后来我决定在Node和ESCPOS模块中实现这一点。

我将此应用程序连接到MySQL数据库，以便能够从记录的交易中打印收据。我正在使用表格来创建产品及其各自价格的列表，但只能通过硬编码。我现在的问题是如何动态创建这些表。根据交易中涉及的产品，我希望脚本仅查询和打印这些产品。

这是收据代码！

const db = require('./database.js');
const escpos = require('escpos');
const uniqueRandom = require('unique-random');
const random = uniqueRandom(1000, 9999);


const device  = new escpos.USB();

const options = { encoding: "GB18030" }

exports.printGeneralReceipt = function(status){
  db.getTransactionDetails(function(res){
    data = res;
  }); 

  const printer = new escpos.Printer(device, options);
  console.log("Printer found!");

  device.open(function(){
    console.log("Receipt generating...");
    printer
    .font('b')
    .align('ct')
    .style('bu')
    .size(1, 1)
    .encode('utf8')
    .text('\n*****START OF LEGAL RECEIPT*****'+
    '\n\nCOMPUTICKET MALAWI\n'+
    'SHOP 31A, GAME COMPLEX\n'+
    'LILONGWE MALL\n\nwww.computicket.mw\n+265 (0) 99 974 7576\n')
    .table(["BUYER NAME :", "CLIFFORD MWALE", ""])
    .table(["RECEIPT # :", random(), ""])
    .table(["DATE: ", "12/AUG/2019", ""])
    .text("----------ITEM LIST----------\n")

    // ITEM LIST STARTS HERE
    .table(["MILK","$2"])
    .table(["PEANUT BUTTER", "$6"])
    // ITEM LIST ENDS HERE

    .text("--------------------------------")
    .table(["TOTAL PRICE", "$8.00", ""])
    .text("Operator: Jon Doe\n-------------------------------\n")
    .barcode('123456789012')
    .text("\n\nTHANK YOU\n\n*****END OF LEGAL RECEIPT*****")
    .beep(1,100)
  .cut().close();
  console.log("Receipt printed!");
});

}

下面是从数据库中提取事务详细信息的函数。我将为您省去创建连接的开销。

exports.getTransactionDetails = function(trans_id){
    var res = "";
    conn.query("SELECT * FROM transactions JOIN products_in_transaction WHERE transactions.trans_id = products_in_transaction.trans_id "+
        " transactions.trans_id = '"+trans_id+"'", 
        function (error, results, fields) {
       for(var i = 0; i < results.length; i++){
         // SOME OPERATION HERE
       }
      });
}

node.js

escpos

回答 2

Stack Overflow用户

发布于 2019-12-18 00:01:23

我将发布一些我使用过的代码，它起作用了；您需要安装html-to-text

const escpos = require('escpos');

    // Select the adapter based on your printer type
    const device  = new escpos.USB();

    const printer = new escpos.Printer(device);


    const cartItems = [
        {category: 'test', price: 80, quantityToSell: 2, title: 'Hosting'},
        {category: 'test1', price: 820, quantityToSell: 63, title: 'Mouse'},
        {category: 'test00', price: 60, quantityToSell: 20, title: 'Sale'},
        {category: 'dvhfgnfgjfjg', price: 20, quantityToSell: 8, title: 'Keyboards'},
        {category: 'dvhfgnfgjfjg', price: 10, quantityToSell: 4, title: 'Keyss'},
        {category: 'dvhfgnfgjfjg', price: 70, quantityToSell: 1, title: 'Test'},
        {category: 'dvhfgnfgjfjg', price: 500, quantityToSell: 12, title: 'Whale oil'},
        {category: 'dvhfgnfgjfjg', price: 560, quantityToSell: 22, title: 'Papers'},
    ]

    // get total per line items
    const totalPerItemList = (item) => {

        let totalPerItem = 0

        totalPerItem = item.quantityToSell * item.price


        return totalPerItem
    }

    // get the total price
    let total = 0;
    for (let cartItem of cartItems) {
        var unitSum  = cartItem.quantityToSell * cartItem.price
        total += unitSum

    }

    // Create our html template, could be an html file on it's own
    const TestTable = `
    <!doctype html>
    <html>
        <head>
            <meta charset="utf-8">
            <title>Testing Title for table</title>            
        </head>   
        <body>
            <div class="invoice-box">
                <table class="receipt-table" cellpadding="0" cellspacing="0" border="0">
                    <thead>
                        <tr class="heading">
                            <th>Item</th>
                            <th>Quantity</th>
                            <th>Unit Price</th>
                            <th>Total</th>
                        </tr>
                    </thead>
                    <tbody>
                        ${cartItems.map(item =>
                            `
                                <tr>
                                    <td>${item.title}</td>
                                    <td>${item.quantityToSell}</td>
                                    <td>${item.price}</td>
                                    <td>${totalPerItemList(item)}</td>
                                </tr>
                            `
                        )}
                    </tbody>
                    <tfoot>
                        <tr>
                            <td>
                                TOTAL:${total}
                            </td>
                        </tr>                                                   
                    </tfoot>
            </table>
            </div>            
        </body>     
    </html>
    `


    const htmlToText = require('html-to-text');

    const text = htmlToText.fromString(TestTable, {
        wordwrap: false,
        tables: ['.receipt-box', '.receipt-table']
    });


    device.open(function(err){

        printer
            .font('a')
            .align('ct')
            .style('bu')
            .size(1, 1)
            .text('Printing Tables Dynamically with epos')
            .text('||||||||||||||||||||||||||')
            .text(text)
            .text('||||||||||||||||||||||||')
            .text('========================')
            .cut()
            .close()
    });

票数 0

Stack Overflow用户

发布于 2021-01-18 00:21:29

我发现做这件事的最快方法是做我自己的项目中做的事情，如

'use strict'

import { app, protocol, BrowserWindow,ipcMain } from 'electron'
import { createProtocol } from 'vue-cli-plugin-electron-builder/lib'
import installExtension, { VUEJS_DEVTOOLS } from 'electron-devtools-installer'
const escpos = require('escpos');
escpos.USB = require('escpos-usb');
const isDevelopment = process.env.NODE_ENV !== 'production' 

// Scheme must be registered before the app is ready
protocol.registerSchemesAsPrivileged([
  { scheme: 'app', privileges: { secure: true, standard: true } }
])
async function createWindow() {
  // Create the browser window.
  const win = new BrowserWindow({
    width: 800,
    height: 600,
    webPreferences: {
      // Use pluginOptions.nodeIntegration, leave this alone
      // See nklayman.github.io/vue-cli-plugin-electron-builder/guide/security.html#node-integration for more info
      nodeIntegration: process.env.ELECTRON_NODE_INTEGRATION
    }
  })
  win.menuBarVisible = false;
  if (process.env.WEBPACK_DEV_SERVER_URL) {
    // Load the url of the dev server if in development mode
    await win.loadURL(process.env.WEBPACK_DEV_SERVER_URL)
    if (!process.env.IS_TEST) win.webContents.openDevTools()
  } else {
    createProtocol('app')
    // Load the index.html when not in development
    win.loadURL('app://./index.html')
  }
}

// Quit when all windows are closed.
app.on('window-all-closed', () => {
  // On macOS it is common for applications and their menu bar
  // to stay active until the user quits explicitly with Cmd + Q
  if (process.platform !== 'darwin') {
    app.quit()
  }
})

app.on('activate', () => {
  // On macOS it's common to re-create a window in the app when the
  // dock icon is clicked and there are no other windows open.
  if (BrowserWindow.getAllWindows().length === 0) createWindow()
})

// This method will be called when Electron has finished
// initialization and is ready to create browser windows.
// Some APIs can only be used after this event occurs.
app.on('ready', async () => {
  if (isDevelopment && !process.env.IS_TEST) {
    // Install Vue Devtools
    try {
      await installExtension(VUEJS_DEVTOOLS)
    } catch (e) {
      console.error('Vue Devtools failed to install:', e.toString())
    }
  }
  createWindow()
})

// Exit cleanly on request from parent process in development mode.
if (isDevelopment) {
  if (process.platform === 'win32') {
    process.on('message', (data) => {
      if (data === 'graceful-exit') {
        app.quit()
      }
    })
  } else {
    process.on('SIGTERM', () => {
      app.quit()
    })
  }
}
function print(load){
  var _message = '';
 device.open(function(){
       _message = 'done'
        printer
        .font('a')
        .align('ct')
        .style('bu')
        .size(0.05, 0.05)
        .text('Road House Magodo')
        .text('Magodo Shopping Arcade Ayodele \r\n Fanoki Magodo Phase I')
        .table(['item','qty','total'])
        load.load.forEach((element)=>{
          return printer.table(element)
        })
        printer.text(`Total:   ${load.total}`)
        if(load.change!='card'){
          printer.text(`Change:   ${load.change}`)
        }else{
          printer.text('Method: Card')
        }
        printer.newLine()
        printer.newLine()
        printer.cut()

        printer
        .font('a')
        .align('ct')
        .style('bu')
        .size(0.05, 0.05)
        .text('Road House Magodo')
        .text('Magodo Shopping Arcade Ayodele \r\n Fanoki Magodo Phase I')
        .table(['item','qty','total'])
        load.load.forEach((element)=>{
          return printer.table(element)
        })
        printer.text(`Total:   ${load.total}`)
        if(load.change!='card'){
          printer.text(`Change:   ${load.change}`)
        }else{
          printer.text('Method: Card')
        }
        printer.newLine()
        printer.newLine()
        printer.cut()
        printer
        .font('a')
        .align('ct')
        .style('bu')
        .size(0.05, 0.05)
        .text('Road House Magodo')
        .text('Magodo Shopping Arcade Ayodele \r\n Fanoki Magodo Phase I')
        .table(['item','qty','total'])
        load.load.forEach((element)=>{
          return printer.table(element)
        })
        printer.text(`Total:   ${load.total}`)
        if(load.change!='card'){
          printer.text(`Change:   ${load.change}`)
        }else{
          printer.text('Method: Card')
        }
        printer.newLine()
        printer.cut()
        printer.close()
      },error=>{
        if(error){
          console.log(error)
          _message = error+'error'
          return
          }
      })
      return _message
}
const device  = new escpos.USB();
const printer = new escpos.Printer(device);
ipcMain.on('print', (_,load) => {
  let _fish =()=>{ 
    return print(JSON.parse(load))
  }
  _.reply(_fish());
})

简单地说，就是传递数组或对象并循环它。

票数 0

页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持

原文链接：

https://stackoverflow.com/questions/57490212

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