UIWebView: No binaryen method succeeded

[Xquick]

I want to use FlareJS wrapped in Cordova and have it rendered in mobile WebView. I have example working in normal browser, but when I run it in WebView (tried UIWebView and WKWebView) it fails with

abort("Assertion failed: no binaryen method succeeded."). Build with -s ASSERTIONS=1 for more info.

Is there something I am missing? Have you tried this?
navigator.userAgent from WebView is:
Mozilla/5.0 (iPhone; CPU iPhone OS 13_1 like Mac OS X) AppleWebKit/605.1.15 (KHTML, like Gecko) Mobile/15E148

Thank you for response.