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https://github.com/jacobbubu/pull-window
https://github.com/jacobbubu/pull-window
Last synced: 15 days ago
JSON representation
- Host: GitHub
- URL: https://github.com/jacobbubu/pull-window
- Owner: jacobbubu
- License: mit
- Created: 2020-05-13T15:50:41.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2023-01-06T05:48:44.000Z (about 2 years ago)
- Last Synced: 2025-01-10T05:35:58.091Z (18 days ago)
- Language: TypeScript
- Homepage:
- Size: 1.26 MB
- Stars: 0
- Watchers: 2
- Forks: 2
- Open Issues: 17
-
Metadata Files:
- Readme: README.md
- Contributing: .github/CONTRIBUTING.md
- License: LICENSE
Awesome Lists containing this project
README
# @jacobbubu/pull-window
[](https://github.com/jacobbubu/pull-window/actions?query=workflow%3A%22Build+and+Release%22)
[](https://coveralls.io/github/jacobbubu/pull-window)
[](https://www.npmjs.com/package/@jacobbubu/pull-window/)
> Rewritten [pull-window](https://github.com/dominictarr/pull-window) in TypeScript.
Aggregate a pull-stream into windows.
Several helpers are provided for particular types of windows,
sliding, tumbling, etc.
And also, a low level.
## Example: "tumbling" window
sum every 10 items.
``` js
import * as pull from 'pull-stream'
import { window } from '@jacobbubu/pull-window'
function everyTen () {
let i = 0
//window calls init with each data item,
//and a callback to close that window.
return window(function (data, cb) {
//if you don't want to start a window here,
//return undefined
if(i !== 0) return
let sum = 0
//else return a function.
//this will be called all data
//until you callback.
return function (end, data) {
if(end) return cb(null, sum)
sum += data
if(++i >= 10) {
i = 0
cb(null, sum)
}
}
}
}
pull(
pull.count(1000),
everyTen(),
pull.log()
)
```
## Example: variable sized window
Each window doesn't have to be the same size...
``` js
import * as pull from 'pull-stream'
import { window } from '@jacobbubu/pull-window'
function groupTo100 () {
let sum = null
return window(function (_, cb) {
if(sum !== null) return
/* sum stuff together until you have 100 or more*/
return function (end, data) {
if(end) return cb(null, sum)
sum += data
if(sum >= 100) {
// copy sum like this, incase the next item
// comes through sync
const _sum = sum
sum = null
cb(null, _sum)
}
}
})
}
pull(
pull.count(1000)
groupTo100(),
pull.log()
)
```
## Example: sliding window
to make more over lapping windows
just return the window function more often.
``` js
import * as pull from 'pull-stream'
import { window } from '@jacobbubu/pull-window'
function sliding () {
return window(function (_, cb) {
let sum = 0
let i = 0
/* sum stuff together until you have 100 or more*/
return function (end, data) {
if(end) return cb(null, sum)
sum += data
if(++i >= 10) {
//in this example, each window gets it's own sum,
//so we don't need to copy it.
cb(null, sum)
}
}
})
}
pull(
pull.count(100)
sliding(),
pull.log()
)
```
## API
### window (start, map)
``` js
window(function startWindow (data, cb) {
//called on each chunk
//including the first one
return function addToWindow (end, data) {
//cb(null, aggregate) when done.
}
}, function mapWindow (start, data) {
//(optional)
//map the window to something that tracks start, also
})
```
By default, windows are mapped to `{start: firstData, data: aggregate}`.
unless you pass in an different `mapWindow` function.
### window.sliding(reduce, size)
reduce every `size` items into a single value, in a sliding window
### window.recent(size, time)
tumbling window that groups items onto an array,
either every `size` items, or within `time` ms,
which ever occurs earliest.
## License
MIT