in packages/sha1-browser/src/crossPlatformSha1.ts [11:19]
constructor(secret?: SourceData) {
if (supportsWebCrypto(locateWindow())) {
this.hash = new WebCryptoSha1(secret);
} else if (isMsWindow(locateWindow())) {
this.hash = new Ie11Sha1(secret);
} else {
throw new Error("SHA1 not supported");
}
}