js base64 decode unicode

Base64 encoding and decoding

function utf8_to_b64( str ) {
  return window.btoa(unescape(encodeURIComponent( str )));
}

function b64_to_utf8( str ) {
  return decodeURIComponent(escape(window.atob( str )));
}

// Usage:
utf8_to_b64('✓ à la mode'); // "4pyTIMOgIGxhIG1vZGU="
b64_to_utf8('4pyTIMOgIGxhIG1vZGU='); // "✓ à la mode"