Function isTokenExpired

isTokenExpired(token: string): boolean
Check if JWT token is expired without cryptographic verification

Examines the token's payload to determine if it has expired by comparing the 'exp' claim with the current timestamp. This check is performed without cryptographic verification, making it suitable for quick expiration checks before attempting more expensive verification operations.

The function safely handles malformed tokens by returning true (expired) for any token that cannot be parsed, ensuring secure-by-default behavior.
Parameters
- token: string
  JWT token string to check for expiration
Returns boolean
True if token is expired or malformed, false if still valid
Example
```
// Check token expiration before verification
const token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...';

if (isTokenExpired(token)) {
  console.log('Token has expired');
  // Redirect to login or refresh token
} else {
  console.log('Token is still valid');
  // Proceed with API request
}
```
Example
```
// Use in authentication middleware for early filtering
if (isTokenExpired(accessToken)) {
  // Try to refresh token instead of verification
  return refreshTokens();
}
```
- Defined in src/shared/utils/auth.ts:530