Can I have an if statement inside a map object to handle null values?

Question

So i'm doing some web scraping of a bunch of products on a page & my code works fine as long as the elements are there, though sometimes when a product is out of stock and an element isn't present on a page I get the following error.

I've tried to put some kind of "If statement" inside the map object though can't get it to work.

//This code works if all the elements are present on the page const productsOnPage = await page.$$eval('.tile-product', as => as.map(productContainer => ({ productTitle: productContainer.querySelector('h3').innerText.trim(), })) ); //I want something like this to handle the null values const productsOnPage = await page.$$eval('.tile-product', as => as.map(productContainer => ({ if ( productContainer.querySelector('h3').innerText.length <= 0 || null ) { productTitle: productContainer.querySelector('h3').innerText.trim(), } else { productTitle: '', } })) );

If null I expect:

productTitle: "";

but i'm getting:

Error: Evaluation failed: TypeError: Cannot read property 'innerText' of null

Hamid Raza Noori · Accepted Answer · 2019-07-23 11:17:02Z

You can use ternary operator, E.g

const productsOnPage = await page.$$eval('.tile-product', as => as.map(productContainer => ({ productTitle: productContainer.querySelector('h3') ? productContainer.querySelector('h3').innerText.trim() : ''; })) );

mflds · Accepted Answer · 2019-07-23 11:44:04Z

People already answered with the correct solution. But I believe an explanation is needed. On your if statement productContainer.querySelector('h3').innerText.length you're checking the length of the innerText property from querySelector('h3'). But you must verify if the querySelector('h3') exists before reading its properties.

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