For Xprinter brand printer

- Add printer model "xprinter"
- Add util function to print CODE128 barcode on Xprinter
- Add util function to optimize CODE128 barcode length

Author: Xelio Cheong

packages/core/src/index.ts

@@ -25,7 +25,7 @@ export interface PrinterOptions {
   width?: number | undefined
 }
 
-export type PrinterModel = null | "qsprinter";
+export type PrinterModel = null | "qsprinter" | "xprinter";
 
 /**
  * 'dhdw', 'dwh' and 'dhw' are treated as 'dwdh'
@@ -642,7 +642,13 @@ export class Printer<AdapterCloseArgs extends []> extends EventEmitter {
     if (type === "CODE128" || type === "CODE93")
       codeLength = utils.codeLength(convertCode);
 
-    this.buffer.write(`${codeLength + convertCode + (options.includeParity ? parityBit : "")}\x00`); // Allow to skip the parity byte
+    if ((this._model === "xprinter") && type === "CODE128") {
+      const code128Data = utils.genCode128forXprinter(convertCode);
+      this.buffer.write(code128Data);
+    } else {
+      this.buffer.write(`${codeLength + convertCode + (options.includeParity ? parityBit : "")}\x00`); // Allow to skip the parity byte
+    }
+
     if (this._model === "qsprinter")
       this.buffer.write(_.MODEL.QSPRINTER.BARCODE_MODE.OFF);
 

packages/core/src/utils.ts

@@ -63,4 +63,56 @@ export function intLowHighHex(input: number, length: number = 1): string {
     input = Math.floor(input / 256);
   }
   return ret;
-}
+}
+
+const SPLIT_REGEX = /(^(?:\d\d){2,})|((?<=\D)(?:(?:\d\d){3,})(?=\d?\D))|((?:\d\d){2,}$)/;
+//                  /(--beginning--)|--------(------middle--)----------|(-----end-----)/
+/**
+ * Helper function for barcode type CODE128, split string into blocks to optimize barcode length
+ * Refer to following Wikipedia page
+ * https://en.wikipedia.org/wiki/Code_128#Barcode_length_optimization_by_Code_128_Type-C
+ * @param {[string]} input 
+ * @returns {[string[]]} blocks of string for optimized CODE128 barcode length
+ */
+export function splitForCode128(str: string): string[] {
+  // No need to match REGEX for short string
+  if(str.length <= 4)
+    return [str];
+
+  // Find 4+ consecutive and even number of digits at the beginning or end
+  // Find 6+ consecutive and even number of digits at the middle
+  //
+  // "12345ABC2345678BCD3456789CDE98765" =>
+  // ["1234","5ABC","234567","8BCD","345678","9CDE9","8765"]
+  return str.split(SPLIT_REGEX).filter(s => s !== "" && s !== undefined);
+}
+
+const USE_CODEC_REGEX = /^((?:\d\d){1,})$/;
+/**
+ * Generate control code to print CODE128 on Xprinter brand printer
+ * Barcode length is optimized
+ * Documentation (Chinese only):
+ * https://www.xprinter.net/companyfile/1/
+ * @param {[string]} input 
+ * @returns {[string]} control code for printing
+ */
+export function genCode128forXprinter(barcode:string): string {
+  const toCodeC = (s:string) => 
+      "{C" + s.match(/\d{2}/g) // split every 2 digit
+              ?.map(num => String.fromCharCode(Number(num))) 
+              ?.join('');
+  
+  const toCodeB = (s:string) => "{B" + s.replace('{','{{');
+
+  const blocks = splitForCode128(barcode)
+  const dataPart = blocks.map(block => USE_CODEC_REGEX.test(block) ? toCodeC(block) : toCodeB(block))
+                          .join('');
+  const dataLength = dataPart.length;
+
+  if (dataLength > 255)
+    throw new Error("Barcode data is too long");
+
+  return String.fromCharCode(dataLength) + dataPart;
+}
+
+

packages/core/test/index.test.ts

@@ -1,7 +1,85 @@
 import { describe, expect, it } from 'vitest'
+import { splitForCode128, genCode128forXprinter } from '../src/utils';
 
 describe('should', () => {
   it('exported', () => {
     expect(1).toEqual(1)
-  })
+  });
+
+  it('Split string to optimized blocks for CODE128 barcode', () => {
+    const inputs: string[] = [];
+    const expected: string[][] = [];
+
+    inputs.push("12");
+    expected.push(["12"]);
+
+    inputs.push("123");
+    expected.push(["123"]);
+
+    inputs.push("1234");
+    expected.push(["1234"]);
+
+    inputs.push("12345");
+    expected.push(["1234", '5']);
+
+    inputs.push("123456789");
+    expected.push(["12345678","9"]);
+
+    inputs.push("123A4567C");
+    expected.push(["123A4567C"]);
+
+    inputs.push("1234A4567C");
+    expected.push(["1234","A4567C"]);
+
+    inputs.push("AAA1234");
+    expected.push(["AAA","1234"]);
+
+    inputs.push("AAA12345");
+    expected.push(["AAA1","2345"]);
+
+    inputs.push("4321AAA1234");
+    expected.push(["4321","AAA","1234"]);
+
+    inputs.push("AAA123456BBB");
+    expected.push(["AAA","123456","BBB"]);
+
+    inputs.push("12345ABC2345678BCD3456789CDE98765");
+    expected.push(["1234","5ABC","234567","8BCD","345678","9CDE9","8765"]);
+
+    inputs.forEach((input,index) => {
+      expect(splitForCode128(input)).toEqual(expected[index]);
+    });
+  });
+
+  it('generate CODE128 barcode printing control code for Xprinter', () => {
+    const inputs: string[] = [];
+    const expected: string[] = [];
+
+    inputs.push("AB");
+    expected.push("\x04{BAB");
+
+    inputs.push("12");
+    expected.push("\x03{C\x0c");
+
+    inputs.push("123456789");
+    expected.push("\x09{C\x0c\x22\x38\x4e{B9");
+
+    inputs.push("1234ABC");
+    expected.push("\x09{C\x0c\x22{BABC");
+
+    inputs.push("ABC1234");
+    expected.push("\x09{BABC{C\x0c\x22");
+
+    inputs.push("AAA123456BBB");
+    expected.push("\x0f{BAAA{C\x0c\x22\x38{BBBB");
+
+    inputs.push("12345ABC2345678BCD3456789CDE98765");
+    expected.push("\x25{C\x0c\x22{B5ABC{C\x17\x2d\x43{B8BCD{C\x22\x38\x4e{B9CDE9{C\x57\x41");
+
+    inputs.forEach((input,index) => {
+      expect(genCode128forXprinter(input)).toEqual(expected[index]);
+    });
+
+  });
 })
+