我收到以下错误：

TypeError: __WEBPACK_IMPORTED_MODULE_0_aws_sdk_global__.util.crypto.lib.
randomBytes is not a function

当我尝试使用我编写的以下代码对用户进行身份验证时：

import { CognitoUserPool, CognitoUserAttribute, CognitoUser, AuthenticationDetails } 
from 'amazon-cognito-identity-js';

let authenticationDetails = new AuthenticationDetails({
    Username: username,
    Password: password
});

let userPool = new CognitoUserPool({
    UserPoolId: 'us-east-1_1TXXXXXXbXX',
    ClientId: '4da8hrXXXXXXXXXXXXmj1'
});

let cognitoUser = new CognitoUser({
    Username: username,
    Pool: userPool
});

// THE ERROR IS THROWN AS SOON AS IT HITS THE BELOW
// STATEMENT
cognitoUser.authenticateUser(authenticationDetails, {
    onSuccess: function (result) {
        console.log('access token + ' + result.getAccessToken().getJwtToken());
    },
    onFailure: function(err) {
        console.log(err);
    }
});

这可能是什么原因？我错过了什么？