How to specify type of UseState output in typescript react

Question

I've got a variable whose initial value I want to be null, but I want to be able to set it as a number as well.

const [intervalId, setIntervalId] = useState(null);

When I write setIntervalId(2); in my code later, it complains that argument type number is not assignable to SetActionState<null>.

What's the proper way to define such a variable in React?

jmk · Accepted Answer · 2021-11-02 16:06:48Z

3

Pretty simple:

const [intervalId, setIntervalId] = useState<null | number>(null);

answered Nov 2, 2021 at 16:06

jmk

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1 Comment

I figured this out literally moments after i asked the question, thank you very much. I'll mark as correct when the timer lets me.