spring authentication using react.js sends gibberish response - reactjs

Question

I have a application in react.js and it's server is in spring boot.
Now I want to implement OAuth2 for user authentication. If user is authenticated, then app can get response from the server.
In my application.properties I have added these:
spring.security.oauth2.client.registration.github.client-id=somekey
spring.security.oauth2.client.registration.github.client-secret=somekeyhere`
In pom.xml I have added these:
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-security</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.security</groupId>
<artifactId>spring-security-oauth2-client</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-security-oauth2-jose</artifactId>
</dependency>
I have create WebSecurityConfiguration like this:
#Configuration
public class WebSecurityConfiguration extends WebSecurityConfigurerAdapter {
#Override
protected void configure(HttpSecurity http) throws Exception {
http.authorizeRequests()
.anyRequest().authenticated()
.and()
.oauth2Login();
}
}
When I try to get any requests like /user in browser it redirects me to login or to create account and everything works fine.
But the problem is I can't use the react.js application anymore, so how can I make the authentication in client portion?