Handcrafted TypeScript library for Redis Stream. Backed by ioRedis (peer dependency)

Install

``sh


ioredis is a peer library, so must be installed


npm install ioredis
npm install -D @types/ioredis
`

Example

`ts
import { deepStrictEqual as equal } from 'assert';
import IORedis from 'ioredis';
import redstream, { objectDataParser } from 'redstream';

// Requisite: on local host,
// - install and start 'redis-server' or
// - run 'docker run -p 6379:6379 -it redis:5' (in a terminal)

main();

async function main() {
// create a ioRedis the ioRedis way (here default everything)
const ioRedis = new IORedis();

//// Default RedStream, string name/value object

// create a default RedStream (string name/value)
const streamDefault = redstream(ioRedis, 'stream1');

// xtrim to 0 for this usecase to make sure the first read match the first xadd
await streamDefault.xtrim(0, true); // true for exact (default is fast/approximate);

const id = await streamDefault.xadd({ 'temperature': '25', 'pressure': '1013.25' });
const result1 = await streamDefault.xread(); // default from id '0' and no count
const entry1 = result1?.entries[0];
equal(entry1?.id, id);
console.log(entry1?.data);
// {temperatur: '25', pressure: '1013.25'}


//// Typed RedStream

// create a dataParser
const metricDataParser = (dataArr: string[], id: string) => {
// Here we use the provided objectDataParser to start to parse the redis stream entry [name, value, ...] array to string
// Note: if value above start with '{' or '[' it will attempt to do a JSON.parse to get the object.
const dataObj = objectDataParser(id, dataArr);
// Then, we return the typed data
return {
temperature: Number(dataObj.temperature),
pressure: Number(dataObj.pressure)
}
} // TS infer return {temperature: number, pressure: number}

// create a typed RedStream from a specicification (with the dataParser above)
const streamTyped = redstream(ioRedis, { key: 'stream1', dataParser: metricDataParser });
// now streamTypes.xadd is TS typed
await streamTyped.xadd({ 'temperature': 15, 'pressure': 800.45 });
const result2 = await streamDefault.xread(id); // after the previous id
console.log(result2?.entries[0].data);
// {temperature: 15, pressure: 800.45}

// all commands, xrange, xrevrange, ... are fully typed now.

await ioRedis.disconnect();
}
`

$3

After the example above:

`ts
// the xread object
const xreadResult = await streamTyped.xread(); // default from 0
console.log(JSON.stringify(xreadResult, null, ' ')); // see below
`

Would return:
`js
{
"key": "stream1",
"qid": "0",
"smallest": "1585504199191-0",
"highest": "1585504199195-0",
"entries": [
{
"id": "1585504199191-0",
"data": {
"temperature": 25,
"pressure": 1013.25
}
},
{
"id": "1585504199195-0",
"data": {
"temperature": 15,
"pressure": 800.45
}
}
]
}
``

Full type definition: readstream.ts