https://github.com/oresoftware/json-parser
Node.js transform stream - takes JSON and parses to objects.
https://github.com/oresoftware/json-parser
nodejs stream transform-stream transform-streams
Last synced: 3 months ago
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Node.js transform stream - takes JSON and parses to objects.
- Host: GitHub
- URL: https://github.com/oresoftware/json-parser
- Owner: ORESoftware
- License: mit
- Created: 2018-09-18T16:58:31.000Z (over 6 years ago)
- Default Branch: master
- Last Pushed: 2019-10-07T21:14:49.000Z (over 5 years ago)
- Last Synced: 2024-08-10T10:39:27.391Z (10 months ago)
- Topics: nodejs, stream, transform-stream, transform-streams
- Language: JavaScript
- Homepage:
- Size: 62.5 KB
- Stars: 2
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: readme.md
- License: license.md
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README
## @oresoftware/json-stream-parser
[](https://www.npmjs.com/package/@oresoftware/json-stream-parser)
### Transform stream
>
> Transforms JSON stream to JS Objects
>
### Installation
```bash
$ npm install '@oresoftware/json-stream-parser'
```
### Import
```js
import {JSONParser} from '@oresoftware/json-stream-parser';
```
### Usage
Right now, the library assumes each separate chunk of json is separated by newline characters.
In the future, we could attempt to use a different delimiting character, as a user-provided input variable.
Recommendations welcome.
## Examples
#### Simple Node.js example:
###### Reading from stdin
```typescript
process.stdin.resume().pipe(new JSONParser()).on('data', d => {
// now we got some POJSOs!
});
```
###### Reading/writing to a tcp socket
```typescript
import * as net from 'net';
const [port,host] = [6970,'localhost'];
const ws = net.createConnection(port, host);
ws.setEncoding('utf8')
.pipe(new JSONParser()) // tcp connection is bidirection/full-duplex .. we send JSON strings each way
.on('data', onData); // we receive data coming from the tcp server here
// and we send data like this:
ws.write(JSON.stringify({'some':'data'}) + '\n', 'utf8', cb); // make sure to include the newline char when you write
```
#### Using bash shell
###### Simple bash example:
```js
const k = cp.spawn('bash');
k.stdin.end(`echo '{"foo":"bar"}\n'`); // make sure to include the newline char when you write
k.stdout.pipe(new JSONParser()).on('data', d => {
// => {foo: 'bar'}
});
```
###### Bash example with bash variables:
```js
const k = cp.spawn('bash');
k.stdin.end(`
foo="medicine"
cat < {
assert.deepStrictEqual(d, {foo: 'medicine'}); // should pass
});
```
### If your JSON has white space (newlines etc)
If you JSON has unescaped newlines, or the JSON is separated by some other character, then use the delimiter option.
```js
new JSONParser({delimiter: '∆∆∆'}); // use 3 alt-j's to separate json chunks, since newlines won't work
```
For other solutions to parsing JSON from CLIs, see:
https://stackoverflow.com/questions/56014438/get-single-line-json-from-aws-cli
### Other options
1. delayEvery: integer
> every x chunks, will use setImmediate to delay processing, good for not blocking the event loop too much.
2. emitNonJSON: boolean
> if there is a line of input that cannot be JSON parsed, it will be emitted as "string", but it will not pushed to output
3. there are some secret options in the code, have a look in `lib/main.ts`