blob: bbf411863d133c6007974b45441b594b19133425 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
|
import { cborx } from '../../deps.ts';
/**
* This encoder should keep CBOR data the same length when data is re-encoded
*
* MOST CRITICALLY, this means the following needs to be true of whatever CBOR library we use:
* - CBOR Map type values MUST decode to JavaScript Maps
* - CBOR tag 64 (uint8 Typed Array) MUST NOT be used when encoding Uint8Arrays back to CBOR
*
* So long as these requirements are maintained, then CBOR sequences can be encoded and decoded
* freely while maintaining their lengths for the most accurate pointer movement across them.
*/
const encoder = new cborx.Encoder({
mapsAsObjects: false,
tagUint8Array: false,
});
/**
* Decode and return the first item in a sequence of CBOR-encoded values
*
* @param input The CBOR data to decode
* @param asObject (optional) Whether to convert any CBOR Maps into JavaScript Objects. Defaults to
* `false`
*/
export function decodeFirst<Type>(input: Uint8Array): Type {
// Make a copy so we don't mutate the original
const _input = new Uint8Array(input);
const decoded = encoder.decodeMultiple(_input) as undefined | Type[];
if (decoded === undefined) {
throw new Error('CBOR input data was empty');
}
/**
* Typing on `decoded` is `void | []` which causes TypeScript to think that it's an empty array,
* and thus you can't destructure it. I'm ignoring that because the code works fine in JS, and
* so this should be a valid operation.
*/
// @ts-ignore 2493
const [first] = decoded;
return first;
}
/**
* Encode data to CBOR
*/
export function encode(input: unknown): Uint8Array {
return encoder.encode(input);
}
|
