React Api call: Displaying only 1st onSubmit but nothing after - reactjs

Question

I have two components, CryptoPrice with a coin prop which calls an API to get the price, and Nav where I search for a coin, and it renders the CryptoPrice component assigning the onSubmit value to CryptoPrice coin prop.
The display works good until I do a second onSubmit from the Nav. When I do a second onSubmit, nothing changes.
App.js code:
import CryptoPrice from "./components/CryptoPrice";
import Nav from "./components/Nav";
function App() {
return (
<div className="App">
<header className="App-header">
<h1>Crypto Prices</h1>
<div className="flex">
<CryptoPrice coin="bitcoin" />
<CryptoPrice coin="ethereum" />
</div>
<div>
<Nav></Nav>
</div>
</header>
</div>
);
}
CryptoPrice component:
import styles from "./css/CryptoPrice.module.css";
export default class CryptoPrice extends React.Component {
constructor(props) {
super(props);
this.state = {
price: [],
url: `https://api.coingecko.com/api/v3/simple/price?ids=${this.props.coin}&vs_currencies=usd`,
};
}
componentDidMount = () => {
this.loadData();
setInterval(this.loadData, 20000);
};
loadData = () => {
fetch(this.state.url)
.then((response) => response.json())
.then((data) => {
let key = Object.keys(data);
return data[key];
})
.then((coin) => {
let price = coin.usd;
this.setState({ price });
});
};
render() {
return (
<div className={styles.padding}>
<h2>{this.props.coin} price</h2>
<div>{this.state.price}$</div>
</div>
);
}
}
Nav Component
import CryptoPrice from "./CryptoPrice";
export default class Nav extends React.Component {
constructor(props) {
super(props);
this.state = {
coin: "",
isSubmitted: false,
};
}
componentDidMount() {
this.setState({ isSubmitted: false });
}
render() {
return (
<div>
<form
onSubmit={(e) => {
e.preventDefault();
this.setState({ isSubmitted: true });
}}
>
<input
type="text"
onChange={(e) => {
this.setState({ coin: e.target.value });
}}
></input>
<input type="submit" value="Add"></input>
</form>
{this.state.isSubmitted && <CryptoPrice coin={this.state.coin} />}
</div>
);
}
}
Thanks so much for any help/feedback

Answer 1

Your issue is because you are setting the url in state so it will not update when the props update. Try changing you fetch function to use props directly(also remember to clear the setInterval when you unmount):
loadData = () => {
fetch(`https://api.coingecko.com/api/v3/simple/price?ids=${this.props.coin}&vs_currencies=usd`)
.then((response) => response.json())
.then((data) => {
let key = Object.keys(data);
return data[key];
})
.then((coin) => {
let price = coin.usd;
this.setState({ price });
});
};