wepy引入crypto.js库报错npm/crypto-js/core.js' is not defined

[lxf-soul]

const Crypto = require('crypto-js');
const Base64 = require('js-base64');

function getSignature(policyEncoded, SecretKey){
// 利用SK对Base64编码后的policy结果进行HMAC-SHA1签名计算
const bytes = Crypto.HmacSHA1(policyEncoded, SecretKey);
// 对计算结果进行Base64编码，得到最终的签名信息
const signature = Crypto.enc.Base64.stringify(bytes);
return signature;
}

module.exports = getSignature
我在js文件中引入