Using an if statement for detecting whether value is returning undefined not working

user_19364533 0
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I'm making an app using React-Use-Cart. I am using the getItem hook to detect changes in the price. Its really simple, and this is how this works: if the item has a quantity more than 0, then it will return the price or if it's 0, then it will return undefined.

So, here is my program -

const totalitem = getItem(products.id).itemTotal;
const totalitem2 = JSON.stringify(totalitem);

and

<h1>{totalitem === "undefined" ? "Zero!" : totalitem2}</h1>

This is not working! When totalitem gets to 0, which is undefined, the React DOM throws an error:

Uncaught TypeError: Cannot read properties of undefined (reading 'itemTotal')

I really don't know how to solve this issue, and I'm pretty sure that this is a common one. Can anyone please help me out? Thanks a lot in advance.

reactjs if-statement undefined javascript
1 Answers

The first problem (which is triggering the error) is due to accessing itemTotal property on undefined. You can use optional chaining to solve this.

const totalitem = getItem(products.id)?.itemTotal;
const totalitem2 = JSON.stringify(totalitem);

The second problem is checking "undefined" as a string. It should be without quotes.

<h1>{totalitem === undefined ? "Zero!" : totalitem2}</h1>
user_9955790
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