How do I encode a Dart string in base64?

Question

I'm working with an API that requires data encoded in base64. How can I encode a simple string in base64?

Answer 1

There is no need to use the crypto package since the core libraries provide built-in support for base64 encoding and decoding.

https://api.dartlang.org/stable/2.1.0/dart-convert/dart-convert-library.html

import 'dart:convert';

main() {
  final str = "Hello world";
  final bytes = utf8.encode(str);
  final base64Str = base64.encode(bytes);
  print(base64Str);
}

Answer 2

It requires a few steps, but encoding a string in base64 is pretty straightforward.

Dart has a function in the package:crypto library, CryptoUtils.bytesToBase64, which takes a list of bytes to encode as base64. In order to get the list of bytes from a Dart string, you can use the UTF8.encode() function in the dart:convert library.

All together, this looks like:

import 'dart:convert';
import 'package:crypto/crypto.dart';

main() {
  var str = "Hello world";
  var bytes = UTF8.encode(str);
  var base64 = CryptoUtils.bytesToBase64(bytes);
  print(base64);
}

---

If you're working inside the browser, then you have the easier option of using the browser's built in btoa function. The above code snippet becomes:

import 'dart:html';

main() {
  var str = "Hello world";
  var base64 = window.btoa(str);
  print(base64);
}