fixed-size-list
v0.3.0
Published
Immutable fixed-length list (a.k.a circular buffer) with an event emitter for Typescript and Javascript
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fixed-size-list
Immutable fixed-length list (a.k.a circular buffer) with an event emitter for Typescript and Javascript
Quick start
npm i fixed-size-list
import { FixedSizeList } from 'fixed-size-list'
const maxSize = 3
const fixedSizeList = new FixedSizeList<number>(maxSize)
// Now it's empty
fixedSizeList.add(1)
// Not it's [ 1 ]
fixedSizeList.add(2)
// Now it's [ 2, 1 ]
fixedSizeList.add(3)
// Now it's [ 3, 2, 1 ]
fixedSizeList.add(4)
// Now it's [ 4, 3, 2 ]
console.log(fixedSizeList.data)
// logs [4,3,2]
fixedSizeList.reset()
// Now it's []
Initial list
You can set initial values easily passing them to the constructor
import { FixedSizeList } from 'fixed-size-list'
const maxSize = 3
const list = [1, 2, 3]
const fixedSizeList = new FixedSizeList<number>(maxSize, list)
// Now it's [ 1, 2, 3 ]
Be aware that the initial list is truncated if it's longer than maxSize
import { FixedSizeList } from 'fixed-size-list'
const maxSize = 2
const list = [1, 2, 3]
const fixedSizeList = new FixedSizeList<number>(maxSize, list)
// Now it's [ 1, 2 ]
// 3 was truncated
Events
FixedSizeList has an event emitter. You can listen to specific events. WARNING! on
returns an unsubscribe function. Do not forget to call it when you no longer need the subscription to unsubscribe.
eventNewItem
It emits an added item
import { FixedSizeList, eventNewItem } from 'fixed-size-list'
const maxSize = 2
const fixedSizeList = new FixedSizeList<number>(maxSize)
const unsubscribe = fixedSizeList.on(eventNewItem, (newItem) => console.log('item added', newItem))
fixedSizeList.add(5)
// logs 'item added 5'
// later on
unsubscribe()
eventTruncate
It emits an array of removed items
import { FixedSizeList, eventTruncate } from 'fixed-size-list'
const maxSize = 2
const fixedSizeList = new FixedSizeList<number>(maxSize)
const unsubscribe = fixedSizeList.on(eventTruncate, (removedItems) =>
console.log('items removed', removedItems.toString()),
)
fixedSizeList.add(5)
fixedSizeList.add(4)
fixedSizeList.add(3)
// logs 'items removed [ 5 ]'
// later on
unsubscribe()
eventReset
import { FixedSizeList, eventReset } from 'fixed-size-list'
const maxSize = 2
const fixedSizeList = new FixedSizeList<number>(maxSize)
const unsubscribe = fixedSizeList.on(eventReset, () => console.log('list reset'))
fixedSizeList.reset()
// logs 'list reset'
// later on
unsubscribe()
eventCreated
We can add the third optional parameter of FixedSizeList's constructor and pass a custom event emitter
import { FixedSizeList, eventCreated, IFixedSizeListEvents } from 'fixed-size-list'
import mitt from 'mitt'
const maxSize = 2
const list = []
const emitter = mitt()
const unsubscribe = emitter.on(eventCreated, () => console.log('list created'))
const fixedSizeList = new FixedSizeList<number>(maxSize, list, emitter)
// logs 'list created'
// later on
unsubscribe()
All
We can subscribe to all events at once
import { FixedSizeList, eventCreated, IFixedSizeListEvents } from 'fixed-size-list'
const fixedSizeList = new FixedSizeList<number>(10)
const unsubscribe = emitter.on('*', () => console.log('Any event'))
// later on
unsubscribe()