Can't create JS function with create_function()

[adityawarmanfw]

Hi, I was trying to register JS function but it throws me this error. Not sure what happened here.

Error Message

(index):1 Uncaught DOMException: Failed to execute 'postMessage' on 'MessagePort': function getFlag(country_code) {
        // just some unicode magic
        return String.fromCodePoint(...Arra...<omitted>... } could not be cloned.
    at https://cdn.skypack.dev/-/sql.js-httpvfs@v0.8.12-0JKSUPpKcT8KmFoPA4hg/dist=es2019,mode=imports/optimized/sql.js-httpvfs.js:157:44
    at new Promise (<anonymous>)
    at E (https://cdn.skypack.dev/-/sql.js-httpvfs@v0.8.12-0JKSUPpKcT8KmFoPA4hg/dist=es2019,mode=imports/optimized/sql.js-httpvfs.js:153:18)
    at Object.apply (https://cdn.skypack.dev/-/sql.js-httpvfs@v0.8.12-0JKSUPpKcT8KmFoPA4hg/dist=es2019,mode=imports/optimized/sql.js-httpvfs.js:113:20)
    at https://adityawarmanfw.id/p/fb3644c1-bad8-4063-8f10-5f6ae4da8806/:59:24
    at async https://adityawarmanfw.id/p/fb3644c1-bad8-4063-8f10-5f6ae4da8806/:54:20