CborSequenceDecoderStream

import { CborSequenceDecoderStream } from "jsr:@ende/cbor";

class

class CborSequenceDecoderStream implements TransformStream<Uint8Array, CborStreamOutput>

A TransformStream that decodes a CBOR-sequence-encoded ReadableStream into the JavaScript equivalent values represented as ReadableStream. RFC 8949 - Concise Binary Object Representation (CBOR)

Limitations:

While CBOR does support map keys of any type, this implementation only supports map keys being of type string, and will throw if detected decoding otherwise.
This decoder does not validate that the encoded data is free of duplicate map keys, and will serve them all. This behaviour differentiates from decodeCbor and decodeCborSequence.
Arrays and Maps will always be decoded as a CborArrayDecodedStream and CborMapDecodedStream, respectively.
"Byte Strings" and "Text Strings" will be decoded as a CborByteDecodedStream and CborTextDecodedStream, respectively, if they are encoded as an "Indefinite Length String" or their "Definite Length" is 2 ** 32 and 2 ** 16, respectively, or greater.

Notice:

This decoder handles the tag numbers 0, and 1 automatically, all others returned are wrapped in a CborTag instance.
If a parent stream yields CborByteDecodedStream, CborTextDecodedStream, CborArrayDecodedStream, CborMapDecodedStream, or CborTag (with any of these types as content), it will not resolve the next chunk until the yielded stream is fully consumed or canceled.

Example: Usage

import { encodeBase64Url } from "@ende/encoding";
import {
  CborArrayDecodedStream,
  CborArrayEncoderStream,
  CborByteDecodedStream,
  CborByteEncoderStream,
  CborMapDecodedStream,
  CborMapEncoderStream,
  type CborStreamOutput,
  CborSequenceDecoderStream,
  CborSequenceEncoderStream,
  CborTag,
  CborTextDecodedStream,
  CborTextEncoderStream,
} from "@ende/cbor";

const rawMessage = [
  undefined,
  null,
  true,
  false,
  3.14,
  5,
  2n ** 32n,
  "Hello World",
  new Uint8Array(25),
  new Date(),
  new CborTag(33, encodeBase64Url(new Uint8Array(7))),
  ["cake", "carrot"],
  { a: 3, b: "d" },
  CborByteEncoderStream.from([new Uint8Array(7)]),
  CborTextEncoderStream.from(["Bye!"]),
  CborArrayEncoderStream.from([
    "Hey!",
    CborByteEncoderStream.from([new Uint8Array(18)]),
  ]),
  CborMapEncoderStream.from([
    ["a", 0],
    ["b", "potato"],
  ]),
];

async function logValue(value: CborStreamOutput) {
  if (
    value instanceof CborByteDecodedStream ||
    value instanceof CborTextDecodedStream
  ) {
    for await (const x of value) console.log(x);
  } else if (value instanceof CborArrayDecodedStream) {
    for await (const x of value) logValue(x);
  } else if (value instanceof CborMapDecodedStream) {
    for await (const [k, v] of value) {
      console.log(k);
      logValue(v);
    }
  } else if (value instanceof CborTag) {
    console.log(value);
    logValue(value.tagContent);
  } else console.log(value);
}

for await (
  const value of ReadableStream.from(rawMessage)
    .pipeThrough(new CborSequenceEncoderStream())
    .pipeThrough(new CborSequenceDecoderStream())
) {
  logValue(value);
}

Constructors

`constructor`

new CborSequenceDecoderStream()

Constructs a new instance.

Methods

`readable`

get readable(): ReadableStream<CborStreamOutput>

The ReadableStream associated with the instance, which provides the decoded CBOR data as CborStreamOutput chunks.

Returns

A ReadableStream.

Example: Usage

import { encodeBase64Url } from "@ende/encoding";
import {
  CborArrayDecodedStream,
  CborArrayEncoderStream,
  CborByteDecodedStream,
  CborByteEncoderStream,
  CborMapDecodedStream,
  CborMapEncoderStream,
  type CborStreamOutput,
  CborSequenceDecoderStream,
  CborSequenceEncoderStream,
  CborTag,
  CborTextDecodedStream,
  CborTextEncoderStream,
} from "@ende/cbor";

const rawMessage = [
  undefined,
  null,
  true,
  false,
  3.14,
  5,
  2n ** 32n,
  "Hello World",
  new Uint8Array(25),
  new Date(),
  new CborTag(33, encodeBase64Url(new Uint8Array(7))),
  ["cake", "carrot"],
  { a: 3, b: "d" },
  CborByteEncoderStream.from([new Uint8Array(7)]),
  CborTextEncoderStream.from(["Bye!"]),
  CborArrayEncoderStream.from([
    "Hey!",
    CborByteEncoderStream.from([new Uint8Array(18)]),
  ]),
  CborMapEncoderStream.from([
    ["a", 0],
    ["b", "potato"],
  ]),
];

async function logValue(value: CborStreamOutput) {
  if (
    value instanceof CborByteDecodedStream ||
    value instanceof CborTextDecodedStream
  ) {
    for await (const x of value) console.log(x);
  } else if (value instanceof CborArrayDecodedStream) {
    for await (const x of value) logValue(x);
  } else if (value instanceof CborMapDecodedStream) {
    for await (const [k, v] of value) {
      console.log(k);
      logValue(v);
    }
  } else if (value instanceof CborTag) {
    console.log(value);
    logValue(value.tagContent);
  } else console.log(value);
}

for await (
  const value of ReadableStream.from(rawMessage)
    .pipeThrough(new CborSequenceEncoderStream())
    .pipeThrough(new CborSequenceDecoderStream())
) {
  logValue(value);
}

`writable`

get writable(): WritableStream<Uint8Array>

The WritableStream associated with the instance, which accepts Uint8Array chunks to be decoded from CBOR format.

Returns

A WritableStream.

Example: Usage

import { encodeBase64Url } from "@ende/encoding";
import {
  CborArrayDecodedStream,
  CborArrayEncoderStream,
  CborByteDecodedStream,
  CborByteEncoderStream,
  CborMapDecodedStream,
  CborMapEncoderStream,
  type CborStreamOutput,
  CborSequenceDecoderStream,
  CborSequenceEncoderStream,
  CborTag,
  CborTextDecodedStream,
  CborTextEncoderStream,
} from "@ende/cbor";

const rawMessage = [
  undefined,
  null,
  true,
  false,
  3.14,
  5,
  2n ** 32n,
  "Hello World",
  new Uint8Array(25),
  new Date(),
  new CborTag(33, encodeBase64Url(new Uint8Array(7))),
  ["cake", "carrot"],
  { a: 3, b: "d" },
  CborByteEncoderStream.from([new Uint8Array(7)]),
  CborTextEncoderStream.from(["Bye!"]),
  CborArrayEncoderStream.from([
    "Hey!",
    CborByteEncoderStream.from([new Uint8Array(18)]),
  ]),
  CborMapEncoderStream.from([
    ["a", 0],
    ["b", "potato"],
  ]),
];

async function logValue(value: CborStreamOutput) {
  if (
    value instanceof CborByteDecodedStream ||
    value instanceof CborTextDecodedStream
  ) {
    for await (const x of value) console.log(x);
  } else if (value instanceof CborArrayDecodedStream) {
    for await (const x of value) logValue(x);
  } else if (value instanceof CborMapDecodedStream) {
    for await (const [k, v] of value) {
      console.log(k);
      logValue(v);
    }
  } else if (value instanceof CborTag) {
    console.log(value);
    logValue(value.tagContent);
  } else console.log(value);
}

for await (
  const value of ReadableStream.from(rawMessage)
    .pipeThrough(new CborSequenceEncoderStream())
    .pipeThrough(new CborSequenceDecoderStream())
) {
  logValue(value);
}

Source