Conditional Navigation Rendering in React

Question

I'm building a simple react app using React v16.7 and MDB (Material Design for Bootstrap). react-router-dom handles my routing system. I want my navigation bar transparent in homepage, and in other pages I want it dark. My code is as follows:

App.js

class App extends Component {

state = {
    collapseID: ""
}

toggleCollapse = collapseID => () =>
    this.setState(prevState => ({
        collapseID: prevState.collapseID !== collapseID ? collapseID : ""
    }));

closeCollapse = collapseID => () =>
    this.state.collapseID === collapseID && this.setState({ collapseID: "" });

render() {

    const overlay = (
        <div
            id="sidenav-overlay"
            style={{ backgroundColor: "transparent" }}
            onClick={this.toggleCollapse("mainNavbarCollapse")}
        />
    );

    const { collapseID } = this.state;

    return (
        <Router>
            <div className="flyout">
                <MDBNavbar color="elegant-color-dark" dark expand="md" fixed="top" scrolling transparent>
                    <MDBContainer>
                        <MDBNavbarBrand href="/">
                            <img src={Logo} height="50" alt="Logo" />
                        </MDBNavbarBrand>
                        <MDBNavbarToggler onClick={this.toggleCollapse("mainNavbarCollapse")} />
                        <MDBCollapse id="mainNavbarCollapse" isOpen={this.state.collapseID} navbar>
                            <MDBNavbarNav right>
                                <MDBNavItem>
                                    <MDBNavLink exact to="/" onClick={this.closeCollapse("mainNavbarCollapse")} >
                                        Home
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={this.closeCollapse("mainNavbarCollapse")} to="/about" >
                                        About
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={this.closeCollapse("mainNavbarCollapse")} to="/products">
                                        Products
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={this.closeCollapse("mainNavbarCollapse")} to="/trading">
                                        Trading
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={this.closeCollapse("mainNavbarCollapse")} to="/contact">
                                        Contact
                                    </MDBNavLink>
                                </MDBNavItem>
                            </MDBNavbarNav>
                        </MDBCollapse>
                    </MDBContainer>
                </MDBNavbar>
                {collapseID && overlay}
                <main style={{ marginTop: "0" }}>
                    <Routes />
                </main>
            </div>
        </Router>
    );
  }
}

export default App;

Routes.js

class Routes extends React.Component {
render() {
    return (
        <Switch>
            <Route exact path="/" component={Home} />
            <Route exact path="/about" component={About} />
            <Route exact path="/products" component={Products} />
            <Route exact path="/trading" component={Trading} />
            <Route exact path="/contact" component={Contact} />
            <Route
                render = {function () {
                    return <h1 className="text-center m-5">Page Not Found</h1>;
                }}
            />
        </Switch>
    );
  }
}

export default Routes;

In App.js, as you can see, <MDBNavbar color="elegant-color-dark" dark expand="md" fixed="top" scrolling transparent> has an attribute transparent. I want it only in homepage. In other pages, it'll be like: <MDBNavbar color="elegant-color-dark" dark expand="md" fixed="top" scrolling>.

I tried using states and props but no luck. How can I solve this issue?

Thanks in advance.

Answer 1

You can use withRouter HOC from react-router (https://github.com/ReactTraining/react-router/blob/master/packages/react-router/docs/api/withRouter.md) to get location in props in NavBar, extracted as a separate component. It would more or less give that ( minus the props missing to NavBar):

               const NavBar = ({location, collapseID, closeCollapse, toggleCollapse}) => <MDBNavbar color={location.pathname === "home"? "elegant-color-dark": ""} dark expand="md" fixed="top" scrolling transparent>
                    <MDBContainer>
                        <MDBNavbarBrand href="/">
                            <img src={Logo} height="50" alt="Logo" />
                        </MDBNavbarBrand>
                        <MDBNavbarToggler onClick={toggleCollapse("mainNavbarCollapse")} />
                        <MDBCollapse id="mainNavbarCollapse" isOpen={collapseID} navbar>
                            <MDBNavbarNav right>
                                <MDBNavItem>
                                    <MDBNavLink exact to="/" onClick={closeCollapse("mainNavbarCollapse")} >
                                        Home
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={closeCollapse("mainNavbarCollapse")} to="/about" >
                                        About
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={closeCollapse("mainNavbarCollapse")} to="/products">
                                        Products
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={closeCollapse("mainNavbarCollapse")} to="/trading">
                                        Trading
                                    </MDBNavLink>
                                </MDBNavItem>
                                <MDBNavItem>
                                    <MDBNavLink onClick={closeCollapse("mainNavbarCollapse")} to="/contact">
                                        Contact
                                    </MDBNavLink>
                                </MDBNavItem>
                            </MDBNavbarNav>
                        </MDBCollapse>
                    </MDBContainer>
                </MDBNavbar>

const NavBarWithRouter = withRouter(NavBar) 

class App extends Component {

state = {
    collapseID: ""
}

toggleCollapse = collapseID => () =>
    this.setState(prevState => ({
        collapseID: prevState.collapseID !== collapseID ? collapseID : ""
    }));

closeCollapse = collapseID => () =>
    this.state.collapseID === collapseID && this.setState({ collapseID: "" });

render() {

    const overlay = (
        <div
            id="sidenav-overlay"
            style={{ backgroundColor: "transparent" }}
            onClick={this.toggleCollapse("mainNavbarCollapse")}
        />
    );

    const { collapseID } = this.state;

    return (
        <Router>
            <div className="flyout">
                <NavBarWithRouter toggleCollapse={this. toggleCollapse} closeCollapse={this.closeCollapse} collapseID={collapseID} />
                {collapseID && overlay}
                <main style={{ marginTop: "0" }}>
                    <Routes />
                </main>
            </div>
        </Router>
    );
  }
}

export default App;

Answer 2

You may use window.location.pathname and match it with the route of the homepage, to conditionally pass props.

Define a props object that you wish to pass, preferably in componentDidMount of App.js:

let homePageProps = {};
if (window.location.pathname === "/") {
  homePageProps.transparent = "transparent";
}

Then spread it.

<MDBNavbar color="elegant-color-dark" dark expand="md" fixed="top" scrolling {...homePageProps}>