Class JsonParseStream

Parse each chunk as JSON.

This can be used to parse JSON lines, NDJSON and JSON Text Sequences. Chunks consisting of spaces, tab characters, or newline characters will be ignored.

Example: Basic usage

import { JsonParseStream } from "@std/json/parse-stream";
import { assertEquals } from "@std/assert";

const stream = ReadableStream.from([
  `{"foo":"bar"}\n`,
  `{"baz":100}\n`
]).pipeThrough(new JsonParseStream());

assertEquals(await Array.fromAsync(stream), [
  { foo: "bar" },
  { baz: 100 }
]);

Example: parse JSON lines or NDJSON from a file

import { TextLineStream } from "@std/streams/text-line-stream";
import { JsonParseStream } from "@std/json/parse-stream";
import { assertEquals } from "@std/assert";

const file = await Deno.open("json/testdata/test.jsonl");

const readable = file.readable
  .pipeThrough(new TextDecoderStream())  // convert Uint8Array to string
  .pipeThrough(new TextLineStream()) // transform into a stream where each chunk is divided by a newline
  .pipeThrough(new JsonParseStream()); // parse each chunk as JSON

assertEquals(await Array.fromAsync(readable), [
 {"hello": "world"},
 ["👋", "👋", "👋"],
 {"deno": "🦕"},
]);
Hierarchy
  • TransformStream<string, JsonValue>
    • JsonParseStream

Constructors

constructor

Properties

readable writable

Constructors

constructor

Properties

Readonlyreadable

readable: ReadableStream<JsonValue>

MDN Reference

Readonlywritable

writable: WritableStream<string>

MDN Reference

Settings

Member Visibility

On This Page

Constructors
Properties