Does useEffect run twice in production?-CodePudding

The question is pretty straight forward. I know that it is supposed to run twice in development to faster identify bugs. But no I ask myself if I need to configure something so it does not happed in production when I deploy my NextJS app.

Here is the issue I am having. So I took some time off programming because of Uni. Now I am trying to fetch some data in useEffect right after render but can't get it to work right.

I could simply do:

    useEffect(() => {
        fetch(`/api/collection/getCollections`)
.then(res => res.json())
.then(data => setData(data.collections))
.catch(error => console.log(error));
    }, [])

Or something like this:

useEffect(() => {
    const getData = async () => {
        await fetch(`/api/collection/getCollections`).then(res => res.json()).then(data => setData(data.collections)).catch(error => console.log(error));
    }
    getData();
}, [])

Which is basically the same thing. But both runs twice and I get two API calls

Thank you in advance!

CodePudding user response：

Check out next.config.js file and make reactStrictMode equal false, then restart the node server. This is why your API gets called twice.

React's Strict Mode is a development mode only feature for highlighting potential problems in an application. It helps to identify unsafe lifecycles, legacy API usage, and a number of other features(see here).

So yes, it is only for development mode.