[Solved]-How to link to Routes inside the component rendered by another Route with React Router-Reactjs

If you need Nested routing inside ComponentB you should add Links for those Routes as well. And use match.url and match.path to build the nested Links and Routes.

const ComponentB = ({ match }) => {
    return (
        <div> 
            <div>
                <ul>
                    <li><Link to={`${match.url}/c`}>Component C</Link></li>

                    // more Links
                    <li><Link to={`${match.url}/css`}>CSS</Link></li>
                    <li><Link to={`${match.url}/react`}>React</Link></li>
                </ul>
            </div>
            <div>
                <Route path={`${match.path}/c`} component={ComponentC} />

                // more nested Routes
                <Route path={`${match.path}/css`} render={() => { return <h1>CSS</h1> }}/>
                <Route path={`${match.path}/react`} render={() => { return <h1>React</h1> }}/>
            </div>
        </div>
    );
}

Nested routing

Components created via Route will automatically be passed the following prop objects: match, location and history.

Using match you can implement nested Routes. The match object contains the following properties:

• params — (object) Key/value pairs parsed from the URL corresponding to the dynamic segments of the path
• isExact — (boolean) true if the entire URL was matched (no trailing characters)
• path — (string) The path pattern used to match. Useful for building nested Routes
• url — (string) The matched portion of the URL. Useful for building nested Links

Reference

1. https://medium.freecodecamp.org/beginners-guide-to-react-router-4-8959ceb3ad58
2. https://medium.com/@pshrmn/a-simple-react-router-v4-tutorial-7f23ff27adf

You can do it in following way:

<Route exact path='/a' component={A} />
<Route path='/b' component={B} />

// Following should be router inside Component B
<Route exact path='/b/abc' component={OtherComponent}

If you want I've prepared few react-router 4 examples. These are hosted here. https://github.com/SandipNirmal/react-router-examples