Yes – it does look like some sort of Javascript error. Possibly clashing with another plugin or your theme.
What I would try is the following:
– Make sure WordPress, your Theme, and all your plugins are updated (including Slide Anything)
– Ensure you do not have any Minify plugins installed
– If you have a Cache plugin installed, clear out the cache
If you are still not having any joy after this , then try disabling all your plugins to see if its a plugin clash.
– If SA is still not working, then re-enable all plugins – it’s not a plugin clash
– If SA is working then there is a plugin class, and you will have to re-enable plugins 1 by 1 (testing if SA works after each one) to find the plaugin which is clashing
Also try activating another theme (e.g. the standard Twenty Seventeen theme) to see if its possibly a clash with the theme.