easy-json-stream

easy-json-stream

Stream objects to JSON and JSON into objects.

npm i easy-json-stream [--save]

Motivation

JSON and object streams arrive to applications in a variety of ways, for example:

• line-separated JSON objects from a database
• a stream of JSON data POST'ed to update a record

To keep the "pipes clean" this module allows for a simple way to process these JSON and/or object streams.

Primarily, this module aims to reduce surface area when writing proper JSON from a number of objects, i.e. separating with commas and wrapping in [] as arrays, etc.

Caveat emptor

There are likely modules that do this exact thing, or probably even better.

For instance, EasyJSONStream#parse buffers the entire stream prior to pushing the parsed JavaScript object. With big JSON payloads this most certainly is not desirable.

Usage

EasyJSONStream#stringify

Concat objects together into valid JSON. This method expects real JavaScript objects and does not do any parsing of the input.

Options:

• head: determines the "start" of the response
• tail: determines the "end" of the response
• sep [default: ',']: determines the separator for each chunk

Notice that multiple chunks are automatically separated by commas. The head and tail are determnined by passing options; there are no defaults for these options.

var easyJSONStream = require('easy-json-stream');

STREAM_OF_DATABASE_ROWS // { one: 1 }{ two: 2 }{ three: 3 }
  .pipe(easyJSONStream.stringify({ head: '[', tail: ']' }))
  .pipe(process.stdout) // => [{ "one": 1 }, { "two": 2 }, { "three": 3 }]
;

EasyJSONStream#parse

Parse a stream of JSON into usable JavaScript objects. If the string is not parseable, an error event is emitted.

Only one data event will be emitted once all JSON is buffered and parsed.

var easyJSONStream = require('easy-json-stream');

STREAM_OF_TEXT // "[{ \"one\": 1 }, {\"two\": 2 }]"
  .pipe(easyJSONStream.parse())
  .on('data', console.log) // [{ one: 1 }, { two: 2 }]