### Install Library

Source: https://github.com/xuannghia/vietnam-qr-pay/blob/master/README.md

Install the package via npm to get started with QR code generation and parsing.

```bash
npm install vietnam-qr-pay
```

--------------------------------

### Generate VietQR codes

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Create static or dynamic VietQR codes for bank transfers. Static QR codes (initMethod '11') contain only account details, while dynamic QR codes (initMethod '12') include transaction amounts and purposes.

```typescript
import { QRPay, BanksObject } from 'vietnam-qr-pay';

// QR Tĩnh - Chỉ có thông tin tài khoản
const staticQR = QRPay.initVietQR({
  bankBin: BanksObject.acb.bin,
  bankNumber: '257678859',
});
const staticContent = staticQR.build();

// QR Động - Có số tiền và nội dung
const dynamicQR = QRPay.initVietQR({
  bankBin: BanksObject.vietcombank.bin,
  bankNumber: '1234567890',
  amount: '500000',
  purpose: 'Thanh toan hoa don',
});
const dynamicContent = dynamicQR.build();
```

--------------------------------

### Generate VietQR Codes

Source: https://github.com/xuannghia/vietnam-qr-pay/blob/master/README.md

Create static or dynamic VietQR codes by initializing the QRPay instance with bank details. Dynamic codes support additional parameters like amount and payment purpose.

```javascript
import { QRPay, BanksObject } from 'vietnam-qr-pay';

// Static QR
const qrPay = QRPay.initVietQR({
  bankBin: BanksObject.acb.bin,
  bankNumber: '257678859',
})
const content = qrPay.build();

// Dynamic QR
const dynamicQr = QRPay.initVietQR({
  bankBin: BanksObject.acb.bin,
  bankNumber: '257678859',
  amount: '10000',
  purpose: 'Chuyen tien',
})
const dynamicContent = dynamicQr.build();
```

--------------------------------

### Initialize and Modify QR Pay Data

Source: https://github.com/xuannghia/vietnam-qr-pay/blob/master/README.md

Demonstrates how to import the QRPay class, parse an existing QR code string, update transaction details like amount and purpose, and generate a new QR code string using the build method.

```javascript
import { QRPay } from 'vietnam-qr-pay';

const qrContent = '00020101021238530010A0000007270123000697041601092576788590208QRIBFTTA5303704540410005802VN62150811Chuyen tien6304BBB8';
const qrPay = new QRPay(qrContent);

// Update transaction details
qrPay.amount = '999999';
qrPay.additionalData.purpose = 'Cam on nhe';

// Generate new QR content
const newQRContent = qrPay.build();
```

--------------------------------

### Access Bank Information via BanksObject

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Explains how to retrieve detailed bank metadata such as BIN, SWIFT codes, and VietQR support status from the library's built-in bank database.

```typescript
import { BanksObject, Banks, VietQRStatus } from 'vietnam-qr-pay';

const acb = BanksObject.acb;
console.log(acb.bin);
console.log(acb.name);

const transferSupported = Banks.filter(
  bank => bank.vietQRStatus === VietQRStatus.TRANSFER_SUPPORTED
);
console.log(transferSupported.length);
```

--------------------------------

### Generate MoMo QR Code

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Shows how to create a VietQR-compliant code for MoMo payments. It utilizes the BVBank BIN and includes specific reference and unreserved fields required by the MoMo ecosystem.

```typescript
import { QRPay, BanksObject } from 'vietnam-qr-pay';

const momoAccountNumber = '99MM24011M34875080';

const momoQR = QRPay.initVietQR({
  bankBin: BanksObject.banviet.bin,
  bankNumber: momoAccountNumber
});

momoQR.additionalData.reference = 'MOMOW2W' + momoAccountNumber.slice(10);
momoQR.setUnreservedField('80', '046');

const content = momoQR.build();
console.log(content);
```

--------------------------------

### Generate ZaloPay QR Code

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Provides a simple implementation for generating ZaloPay QR codes using the standard VietQR initialization method via the BVBank gateway.

```typescript
import { QRPay, BanksObject } from 'vietnam-qr-pay';

const zaloPayAccountNumber = '99ZP24009M07248267';

const zaloPayQR = QRPay.initVietQR({
  bankBin: BanksObject.banviet.bin,
  bankNumber: zaloPayAccountNumber
});

const content = zaloPayQR.build();
console.log(content);
```

--------------------------------

### Accessing QRPay Object Properties

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Demonstrates how to decode a QR string into a QRPay object and access its properties, including transaction details, provider info, consumer/merchant data, and additional fields.

```typescript
import { QRPay } from 'vietnam-qr-pay';

const qr = new QRPay('00020101021238530010A0000007270123000697041601092576788590208QRIBFTTA5303704540410005802VN62150811Chuyen tien6304BBB8');

console.log(qr.isValid);
console.log(qr.amount);
console.log(qr.provider.name);
console.log(qr.consumer.bankNumber);
console.log(qr.additionalData.purpose);
```

--------------------------------

### Generate E-Wallet QR (MoMo/ZaloPay)

Source: https://github.com/xuannghia/vietnam-qr-pay/blob/master/README.md

Generate QR codes for MoMo and ZaloPay by utilizing the BVBank integration. MoMo requires specific reference data and unreserved fields for proper identification.

```javascript
import { QRPay, BanksObject } from 'vietnam-qr-pay';

// MoMo
const momoQR = QRPay.initVietQR({ bankBin: BanksObject.banviet.bin, bankNumber: '99MM24011M34875080' });
momoQR.additionalData.reference = 'MOMOW2W34875080';
momoQR.setUnreservedField('80', '046');
const momoContent = momoQR.build();

// ZaloPay
const zaloPayQR = QRPay.initVietQR({ bankBin: BanksObject.banviet.bin, bankNumber: '99ZP24009M07248267' });
const zaloContent = zaloPayQR.build();
```

--------------------------------

### Generating and Verifying CRC Codes

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Shows how to calculate the CRC16-CCITT checksum for a QR content string and verify the integrity of a complete QR code string.

```typescript
import { QRPay } from 'vietnam-qr-pay';

const contentWithoutCRC = '00020101021138530010A0000007270123000697041601092576788590208QRIBFTTA53037045802VN6304';
const crcCode = QRPay.genCRCCode(contentWithoutCRC);
const fullQRContent = contentWithoutCRC + crcCode;

const qr = new QRPay(fullQRContent);
console.log(qr.isValid); // true
```

--------------------------------

### Rebuild and Modify QR Code

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Demonstrates how to decode an existing QR string into a QRPay object, update specific fields like amount or purpose, and rebuild it into a new valid QR string.

```typescript
import { QRPay } from 'vietnam-qr-pay';

const originalContent = '00020101021238530010A0000007270123000697041601092576788590208QRIBFTTA5303704540410005802VN62150811Chuyen tien6304BBB8';
const qrPay = new QRPay(originalContent);

qrPay.amount = '999999';
qrPay.additionalData.purpose = 'Cam on nhe';

const newContent = qrPay.build();
console.log(newContent);

const verifyQR = new QRPay(newContent);
console.log(verifyQR.isValid);
```

--------------------------------

### Generate VNPay QR

Source: https://github.com/xuannghia/vietnam-qr-pay/blob/master/README.md

Generate merchant-specific QR codes for VNPay using merchant identification details.

```javascript
const qrPay = QRPay.initVNPayQR({
  merchantId: '0102154778',
  merchantName: 'TUGIACOMPANY',
  store: 'TU GIA COMPUTER',
  terminal: 'TUGIACO1',
});
const content = qrPay.build();
```

--------------------------------

### Generate VNPay Merchant QR codes

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Generate QR codes for merchants using the VNPay standard. This method accepts parameters such as merchant ID, store name, terminal ID, and transaction details to build a compliant QR string.

```typescript
import { QRPay } from 'vietnam-qr-pay';

const vnpayQR = QRPay.initVNPayQR({
  merchantId: '0102154778',
  merchantName: 'TUGIACOMPANY',
  store: 'TU GIA COMPUTER',
  terminal: 'TUGIACO1',
  amount: '1500000',
  purpose: 'Thanh toan laptop',
  billNumber: 'INV2024001',
  reference: 'REF123456',
});

const content = vnpayQR.build();
```

--------------------------------

### Decode QR Codes

Source: https://github.com/xuannghia/vietnam-qr-pay/blob/master/README.md

Parse existing QR code strings to extract provider information, consumer details, amounts, and additional metadata.

```javascript
import { QRPay } from 'vietnam-qr-pay';

const qrContent = '...'; // QR string
const qrPay = new QRPay(qrContent);
console.log(qrPay.isValid);
console.log(qrPay.provider.name);
console.log(qrPay.amount);
```

--------------------------------

### Setting EMVCo and Unreserved Fields

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Illustrates how to add custom data to a QR code using EMVCo (ID 65-79) and Unreserved (ID 80-99) fields to support specific payment requirements.

```typescript
import { QRPay, BanksObject } from 'vietnam-qr-pay';

const qr = QRPay.initVietQR({
  bankBin: BanksObject.banviet.bin,
  bankNumber: '99MM24011M34875080',
});

qr.setUnreservedField('80', '046');
qr.setEVMCoField('65', 'evmco_data_1');

const content = qr.build();
```

--------------------------------

### Decode and validate QR codes

Source: https://context7.com/xuannghia/vietnam-qr-pay/llms.txt

Parse existing QR code strings to extract payment information. The library automatically validates the CRC checksum and provides access to provider details, consumer/merchant info, and transaction metadata.

```typescript
import { QRPay } from 'vietnam-qr-pay';

// Decode VietQR
const vietQRContent = '00020101021238530010A0000007270123000697041601092576788590208QRIBFTTA5303704540410005802VN62150811Chuyen tien6304BBB8';
const vietQR = new QRPay(vietQRContent);
console.log(vietQR.isValid); // true

// Decode VNPayQR
const vnpayContent = '00020101021126280010A000000775011001087990425204597753037045802VN5909MYPHAMHER6005HANOI62260311MY PHAM HER0707MPHER0163041C50';
const vnpayQR = new QRPay(vnpayContent);
console.log(vnpayQR.isValid); // true
```

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