jsonlines-web

Web stream based jsonlines decoder/encoder

✅browser
✅Deno
✅Node.js

This library supports JSON in the following formats:

Line-delimited JSON (JSONLinesStream)
- NDJSON
- JSON lines
Record separator-delimited JSON (JSONLinesStream)
Concatenated JSON (ConcatenatedJSONStream)

See wikipedia for the use of each JSON.

install or import

Deno

import {
  ConcatenatedJSONStream,
  JSONLinesStream,
} from "https://deno.land/x/jsonlines@v0.0.5/mod.ts";

browser

import {
  ConcatenatedJSONStream,
  JSONLinesStream,
} from "https://deno.land/x/jsonlines@v0.0.5/js/mod.js";

Usage

A working example can be found at ./testdata/test.ts.

How to parse JSON Lines

./json-lines.jsonl

{"some":"thing"}
{"foo":17,"bar":false,"quux":true}
{"may":{"include":"nested","objects":["and","arrays"]}}

import { JSONLinesStream } from "https://deno.land/x/jsonlines@v0.0.5/mod.ts";

const { body } = await fetch(
  "https://deno.land/x/jsonlines@v0.0.5/testdata/json-lines.jsonl",
);

const readable = body!
  .pipeThrough(new TextDecoderStream())
  .pipeThrough(new JSONLinesStream());

for await (const data of readable) {
  console.log(data);
}

How to parse json-seq

./json-seq.json-seq

{"some":"thing\n"}
{
  "may": {
    "include": "nested",
    "objects": [
      "and",
      "arrays"
    ]
  }
}

import { JSONLinesStream } from "https://deno.land/x/jsonlines@v0.0.5/mod.ts";

const { body } = await fetch(
  "https://deno.land/x/jsonlines@v0.0.5/testdata/json-seq.json-seq",
);

const recordSeparator = "\x1E";
const readable = body!
  .pipeThrough(new TextDecoderStream())
  .pipeThrough(new JSONLinesStream({ separator: recordSeparator }));

for await (const data of readable) {
  console.log(data);
}

How to parse concat-json

./concat-json.concat-json

{"foo":"bar"}{"qux":"corge"}{"baz":{"waldo":"thud"}}

import { ConcatenatedJSONStream } from "https://deno.land/x/jsonlines@v0.0.5/mod.ts";

const { body } = await fetch(
  "https://deno.land/x/jsonlines@v0.0.5/testdata/concat-json.concat-json",
);

const readable = body!
  .pipeThrough(new TextDecoderStream())
  .pipeThrough(new ConcatenatedJSONStream());

for await (const data of readable) {
  console.log(data);
}

limit

When parsing concat-json, it cannot be parsed unless it is blank immediately after the number, null, true and false.

In other words, this cannot be parsed:

100 200{"foo": "bar"}

But this can be parsed:

100 200 {"foo": "bar"}

note

This library contains ReadableStream.prototype[Symbol.asyncIterator] polyfills. Importing this library will automatically enable ReadableStream.prototype[Symbol.asyncIterator].

develop

need to manually deno task transpile before release.