NativeScript/tns-core-modules/http/http-request/http-request-common.ts

import * as fsModule from "../../file-system";

export function getFilenameFromUrl(url: string) {
    const fs: typeof fsModule = require("file-system");
    const slashPos = url.lastIndexOf('/') + 1;
    const questionMarkPos = url.lastIndexOf('?');

    let actualFileName: string;
    if (questionMarkPos !== -1) {
        actualFileName = url.substring(slashPos, questionMarkPos);
    } else {
        actualFileName = url.substring(slashPos);
    }
    
    const result = fs.path.join(fs.knownFolders.documents().path, actualFileName);
    return result;
}