Base64 encode a javascript object

Question

I have large Javascript objects which I would like to encode to base-64 for AWS Kinesis` It turns out that:

let objStr = new Buffer(JSON.stringify(obj), 'ascii');
new Buffer(objStr, 'base64').toString('ascii') !== objStr

I'm trying to keep this as simple as possible.

How can I base-64 encode JSON and safely decode it back to its original value?

Well, I'm trying to do with `base-64` what `JSON.parse(JSON.stringify(obj))` does on objects. How can I do that? — johni, Jun 30 '16 at 22:26
Would url-encoding work, too? The resultant string might be smaller than if it's base 64-encoded. — David Ehrmann, Jun 30 '16 at 22:32

score 153 · Answer 1 · edited Jun 24 '19 at 08:10

153

From String to Base-64

var obj = {a: 'a', b: 'b'};
var encoded = btoa(JSON.stringify(obj))

To decode back to actual

var actual = JSON.parse(atob(encoded))

For reference look here.

https://developer.mozilla.org/en/docs/Web/API/WindowBase64/Base64_encoding_and_decoding

edited Jun 24 '19 at 08:10

user1063287

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answered Jun 30 '16 at 22:39

Zohaib Ijaz

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11

Have you tried this with non ASCII characters? atob and btoa are quite broken. – Kugel Jul 10 '18 at 07:42
3

this won't work with not escaped charecters in JSON – Bender Oct 17 '19 at 10:22
1

@Bender can you please give an example? – roshnet Jun 01 '20 at 01:28
@Kugel Any other solution available ? – Mo. Jan 07 '22 at 09:26

xiaofeng.li · Accepted Answer · 2018-02-06T22:56:24.000

81

You misunderstood the Buffer(str, [encoding]) constructor, the encoding tells the constructor what encoding was used to create str, or what encoding the constructor should use to decode str into a byte array.

Basically the Buffer class represents byte streams, it's only when you convert it from/to strings that encoding comes into context.

You should instead use buffer.toString("base64") to get base-64 encoded of the buffer content.

let objJsonStr = JSON.stringify(obj);
let objJsonB64 = Buffer.from(objJsonStr).toString("base64");

edited Feb 06 '18 at 22:56

answered Jun 30 '16 at 22:41

xiaofeng.li

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Thanks for the explanation. Regarding your example - it does not work on large JSONs. I've just checked that, the decode returns only partial of the original JSON. – johni Jun 30 '16 at 22:42
How big is your JSON? I tried some large ones and it's working fine. – xiaofeng.li Jun 30 '16 at 22:54
Yep, you're right. I probably selected only part of the encoded string. – johni Jun 30 '16 at 22:55
3

`new Buffer()` is now deprecated, you should use `Buffer.from()` instead, see [the doc](https://nodejs.org/api/buffer.html#buffer_class_method_buffer_from_string_encoding) – Cinn Oct 13 '17 at 14:14

GD21 · Answer 3 · 2023-04-04T14:37:27.317

You can easily encode and decode from and to JSON/Base64 using a Buffer:

JSON to Base64:

function jsonToBase64(object) {
  const json = JSON.stringify(object);
  return Buffer.from(json).toString("base64");
}

Base64 to JSON:

function base64ToJson(base64String) {
  const json = Buffer.from(base64String, "base64").toString();
  return JSON.parse(json);
}

atob() and btoa() are outdated and should no longer be used.

score 2 · Answer 4 · edited Nov 15 '20 at 22:23

2

When converting object to base64 I was getting out of latin range issues and character invalid error.

I made it work in my project with the below line.

Include the base64 and utf8 node packages and access them like this:

var bytes = base64.encode(utf8.encode(JSON.stringify(getOverviewComments())));

edited Nov 15 '20 at 22:23

Ruben Helsloot

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answered Nov 22 '19 at 14:21

Raphael

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Base64 encode a javascript object

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