Base64 URL safe, https://jsfiddle.net/magikMaker/7bjaT/

Base64 URL safe.js

/**
 * use this to make a Base64 encoded string URL friendly, 
 * i.e. '+' and '/' are replaced with '-' and '_' also any trailing '=' 
 * characters are removed
 *
 * @param {String} str the encoded string
 * @returns {String} the URL friendly encoded String
 */
function Base64EncodeUrl(str){
    return str.replace(/\+/g, '-').replace(/\//g, '_').replace(/\=+$/, '');
}

/**
 * Use this to recreate a Base64 encoded string that was made URL friendly 
 * using Base64EncodeurlFriendly.
 * '-' and '_' are replaced with '+' and '/' and also it is padded with '+'
 *
 * @param {String} str the encoded string
 * @returns {String} the URL friendly encoded String
 */
function Base64DecodeUrl(str){
    str = (str + '===').slice(0, str.length + (str.length % 4));
    return str.replace(/-/g, '+').replace(/_/g, '/');
}

/**
 * Example:
 * This Base64 encoded string will be made URL friendly
 */
var encoded = 'VGhpcyBpcyBhbiBhd2Vzb21lIHNjcmlwdA==';

var url_encoded = Base64EncodeUrl(encoded);
var url_decoded = Base64DecodeUrl(url_encoded);

document.write(encoded + '<br />');
document.write(url_encoded + '<br />');
document.write(url_decoded + '<hr />');

// "Test"
document.write(url_decoded === encoded);




PHP:
//Start cleaning url as in
      // to decode base64 for url
      //https://gist.github.com/geongeorge/c30e9b1e3e7590b8a22464c879ad9a04

      $file64 .= "===";

      $file64 = substr($file64,0,strlen($file64) + (strlen($file64)%4));

      $file64 = str_replace('-', '+', $file64);
      $file64 = str_replace('_', '/', $file64);
      $file64 = str_replace(',', '\\', $file64);

      $url = urldecode(base64_decode($file64));

      //Stop cleaning url as in

Javascript

function hashEncodeUrl(str) {
    const mystr = str.replace(/\\/g, "\\\\") // escaping \
    return btoa(encodeURIComponent(mystr))
        .replace(/\+/g, "-")
        .replace(/\//g, "_") //  /..
        .replace(/\\/g, ",") //  \
        .replace(/\=+$/, "") // eslint-disable-line
}

function hashDecodeUrl(str) {
    str = (str + '===').slice(0, str.length + (str.length % 4));

    const initial = str
        .replace(/-/g, '+')
        .replace(/_/g, '/')
        .replace(/,/g, '\\') //  escape slash

    return decodeURIComponent(atob(initial))

}

Node js as window.atob is not available in the node environment

const decode = (str: string): string =>
 Buffer.from(str, 'base64').toString('binary');

const encode = (str: string): string =>
 Buffer.from(str, 'binary').toString('base64');

export const hashEncodeUrl = (str) => {
 if (!str) return '';
 const mystr = str.replace(/\\/g, '\\\\'); // escaping \
 return encode(encodeURIComponent(mystr))
   .replace(/\+/g, '-')
   .replace(/\//g, '_') //  /..
   .replace(/\\/g, ',') //  \
   .replace(/\=+$/, "") // eslint-disable-line
};

export const hashDecodeUrl = (str) => {
 if (!str) return '';
 str = (str + '===').slice(0, str.length + (str.length % 4));

 const initial = str.replace(/-/g, '+').replace(/_/g, '/').replace(/,/g, '\\'); //  escape slash

 return decodeURIComponent(decode(initial));
};