flutter_paydemo/server/src/utils/id.js

/**
 * ID 生成工具
 */
const { nanoid } = require('nanoid');

/** 生成支付单 ID，形如 pay_xxxxxxxx */
function paymentId() {
  return `pay_${nanoid(8)}`;
}

/** 生成商户订单号（外部交易号），形如 20260806_xxxxxxxx */
function outTradeNo() {
  const d = new Date();
  const pad = (n) => String(n).padStart(2, '0');
  const stamp =
    `${d.getFullYear()}${pad(d.getMonth() + 1)}${pad(d.getDate())}` +
    `${pad(d.getHours())}${pad(d.getMinutes())}${pad(d.getSeconds())}`;
  return `${stamp}_${nanoid(6)}`;
}

module.exports = { paymentId, outTradeNo };