nodejs-alipay v1.0.7

var fs = require('fs');
var Alipay = require('./index');

var pay = new Alipay({
rquestUrl: 'https://openapi.alipaydev.com/gateway.do',
app_id: 'XXXXXXX',
return_url: 'http://XXXXX/alipay_return',
notify_url: 'http://XXXXX/bl/alipay_notify',
app_private_key: fs.readFileSync('./pem/private_2048.txt'), //支付宝商户应用私钥
alipay_public_key: fs.readFileSync('./pem/public_2048.txt'),
});

var paramStr = pay.buildSignOrderParam({
boby: '余额充值',
subject: '余额充值',
out_trade_no: new Date().getTime(),
total_amount: 1,
product_code: 'FAST_INSTANT_TRADE_PAY'
});

console.log(paramStr)