You are a cybersecurity analyst tasked with conducting a code review for an authentication and access control system implemented in JavaScript. The system is responsible for verifying user identities and enforcing access permissions to sensitive resources. Your objective is to identify security vulnerabilities in the code and develop comprehensive mitigation strategies to enhance the system's security posture.

Conduct a detailed code review of one of the implementations $($JavaScript$)($Choose any language of your choice as they are identical but different syntax$)$ to identify potential vulnerabilities.

Evaluate the severity and potential impact of the identified vulnerabilities, considering factors such as the likelihood of exploitation and the impact on the confidentiality, integrity, and availability of the system.

Finally, develop comprehensive mitigation strategies to address the identified vulnerabilities, incorporating both technical measures $($e$.$g$.,$ code fixes, security controls$)$ and non$-$technical measures $($e$.$g$.,$ user training, security policies$).$

Evaluate the code of your choice and discuss based on the below

Code $1$ JavaScript