JSON.Stringify as a readable stream. This version has been updated with a maxDepth option.
npm install @inkarnaterpg/json-stream-stringify[![NPM version][npm-image]][npm-url]
[![License][license-image]](LICENSE)
JSON Stringify as a Readable Stream with rescursive resolving of any readable streams and Promises.
- Import formatting has changed
- CJS output added
- Completely rewritten from scratch
- 100% Code Coverage! 🎉
- Space argument finally implemented! 🎉
- ⚠️ Cycling is off by default
- ⚠️ JsonStreamStringify is now a constructor; use `new operator
- Removed dependency on global JSON.stringify, Async/Await and Generators
- JsonStreamStringify is now compiled with babel to target ES5 (polyfills needed)
- Rejected promises and input stream errors are now handled and emitted as errors
- Added cyclic structure detection to prevent infinite recursion
- 🆕 Converted to Typescript
- Promises are rescursively resolved and the result is piped through JsonStreamStringify
- Streams (Object mode) are recursively read and output as arrays
- Streams (Non-Object mode) are output as a single string
- Output is streamed optimally with as small chunks as possible
- Cycling of cyclical structures and dags using Douglas Crockfords cycle algorithm*
- Great memory management with reference release after processing and WeakMap/Set reference handling
- Optimal stream pressure handling
- Tested and runs on ES5, ES2015, ES2016 and later
- Bundled as UMD and Module
\* Off by default since v2
\** With polyfills
`bash`
pnpm add @inkarnaterpg/json-stream-stringify
Using Node v8 or later with ESM / Webpack / Browserify / Rollup
`javascript`
import { JsonStreamStringify } from 'json-stream-stringify';
install @babel/runtime-corejs3 and corejs@3
`javascript`
import { JsonStreamStringify } from 'json-stream-stringify/polyfill';
import { JsonStreamStringify } from 'json-stream-stringify/module.polyfill'; // force ESM
`javascript`
const { JsonStreamStringify } = require('json-stream-stringify'); // let module resolution decide UMD or CJS
const { JsonStreamStringify } = require('json-stream-stringify/umd'); // force UMD
const { JsonStreamStringify } = require('json-stream-stringify/cjs'); // force CJS
`javascript`
const { JsonStreamStringify } = require('json-stream-stringify/polyfill');
const { JsonStreamStringify } = require('json-stream-stringify/umd/polyfill');
const { JsonStreamStringify } = require('json-stream-stringify/cjs/polyfill');
Note: This library is primarily written for LTS versions of NodeJS. Other environments are not tested.
Note on non-NodeJS usage: This module depends on node streams library. Any Streams3 compatible implementation should work - as long as it exports a Readable class, with instances that looks like readable streams.
Note on Polyfills: I have taken measures to minify global pollution of polyfills but this library does not load polyfills by default because the polyfills modify native object prototypes and it goes against the W3C recommendations.
Streaming conversion of value to JSON string.
#### Parameters
- value Any
Data to convert to JSON.
- replacer Optional Function(key, value) or Array
As a function the returned value replaces the value associated with the key. Details
As an array all other keys are filtered. Details
- spaces Optional String or Number
A String or Number object that's used to insert white space into the output JSON string for readability purposes. If this is a Number, it indicates the number of space characters to use as white space. If this is a String, the string is used as white space. If this parameter is not recognized as a finite number or valid string, no white space is used.
- cycle Optional Boolean
true enables cycling of cyclical structures and dags.
To restore cyclical structures; use Crockfords Retrocycle method on the parsed object (not included in this module).
- maxDepth Optional Number
When maxDepth is set, objects nested deeper than the maxDepth will be parsed all at once.
#### Returns
- JsonStreamStringify object that exposes a Streams3 interface.
Get current path begin serialized.
#### Returns
- Array[String, Number]
Array of path Strings (keys of objects) and Numbers (index into arrays).
Can be transformed into an mpath with .join('.').
Useful in conjunction with .on('error', ...), for figuring out what path may have caused the error.
`javascript
const { JsonStreamStringify } = require('json-stream-stringify');
const jsonStream = new JsonStreamStringify({
// Promises and Streams may resolve more promises and/or streams which will be consumed and processed into json output
aPromise: Promise.resolve(Promise.resolve("text")),
aStream: ReadableObjectStream({a:1}, 'str'),
arr: [1, 2, Promise.resolve(3), Promise.resolve([4, 5]), ReadableStream('a', 'b', 'c')],
date: new Date(2016, 0, 2)
});
jsonStream.once('error', () => console.log('Error at path', jsonStream.stack.join('.')));
jsonStream.pipe(process.stdout);
`
Output (each line represents a write from jsonStreamStringify)
`text`
{
"aPromise":
"text"
"aStream":
[
{
"a":
1
}
,
"str"
]
"arr":
[
1
,
2
,
3
,
[
4
,
5
]
,
"
a
b
c
"
],
"date":
"2016-01-01T23:00:00.000Z"
}
`javascript`
app.get('/api/users', (req, res, next) => {
res.type('json'); // Required for proper handling by test frameworks and some clients
new JsonStreamStringify(Users.find().stream()).pipe(res);
});
install @types/readable-stream or @types/node or create your own stream.d.ts that exports a Readable` class.
Copyright (c) 2016 Faleij faleij@gmail.com
[npm-image]: https://img.shields.io/npm/v/@inkarnaterpg/json-stream-stringify.svg
[npm-url]: https://npmjs.org/package/@inkarnaterpg/json-stream-stringify
[license-image]: https://img.shields.io/badge/license-MIT-blue.svg