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useEffect Hook

React.js docs for useEffect

Here's a simple example of how to use React's useState with useEffects.

Cleaning up an Effect

[@react.component]
let make = () => {
    React.useEffect0(() => {
        let id = subscription.subscribe();
        /* clean up the subscription */
        Some(() => subscription.unsubscribe(id));
    });
}

Conditionally Firing an Effect

With this, the subscription will only be recreated when ~source changes

[@react.component]
let make = (~source) => {
    React.useEffect1(() => {
        let id = subscription.subscribe();
        /* clean up the subscription */
        Some(() => subscription.unsubscribe(id));
    }, [|source|]);
}