Swiper 9.0.2 + React 18.2.0 in StrictMode - Cannot read properties of undefined (reading 'slideClass')

[ScorpAL]

Check that this is really a bug

• I confirm

Reproduction link

https://codesandbox.io/s/swiper-9-react-strict-issue-c83d98

Bug description

Swiper 9.0.2 + React 18.2.0 in StrictMode

If you set loading='lazy' to image element inside SwiperSlide and set React.StrictMode you will see error message

Uncaught TypeError: Cannot read properties of undefined (reading 'slideClass')
    at slideSelector (process-lazy-preloader.js:2:1)
    at processLazyPreloader (process-lazy-preloader.js:3:1)
    at HTMLImageElement.<anonymous> (core.js:484:1)

swiper/src/shared/process-lazy-preloader.js

Line 2 in 9fe9a96

const slideSelector = () => (swiper.isElement ? `swiper-slide` : `.${swiper.params.slideClass}`);

I know that lazy loading reimplemented in Swiper 9.

Is it possible to avoid execution of processLazyPreloader if developer don't want to use preloader spinners?

Expected Behavior

Native lazy loading working without issues in console in React.StrictMode

Actual Behavior

Errors in console:

Uncaught TypeError: Cannot read properties of undefined (reading 'slideClass')
    at slideSelector (process-lazy-preloader.js:2:1)
    at processLazyPreloader (process-lazy-preloader.js:3:1)
    at HTMLImageElement.<anonymous> (core.js:484:1)

Swiper version

9.0.2

Platform/Target and Browser Versions

Win/Mac, Chrome

Validations

• Follow our Code of Conduct
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.
• Make sure this is a Swiper issue and not a framework-specific issue

Would you like to open a PR for this bug?

• I'm willing to open a PR

[nolimits4web]

fixed in 4ea0102