check-ethereum-scanner
Version:
Safety checks for new Ethereum tokens
18 lines (16 loc) • 847 B
JavaScript
export function polyfillNeeded(self) {
if (self.__FORCE_INSTALL_ABORTCONTROLLER_POLYFILL) {
console.log('__FORCE_INSTALL_ABORTCONTROLLER_POLYFILL=true is set, will force install polyfill');
return true;
}
// Note that the "unfetch" minimal fetch polyfill defines fetch() without
// defining window.Request, and this polyfill need to work on top of unfetch
// so the below feature detection needs the !self.AbortController part.
// The Request.prototype check is also needed because Safari versions 11.1.2
// up to and including 12.1.x has a window.AbortController present but still
// does NOT correctly implement abortable fetch:
// https://bugs.webkit.org/show_bug.cgi?id=174980#c2
return (
(typeof self.Request === 'function' && !self.Request.prototype.hasOwnProperty('signal')) || !self.AbortController
);
}