round-robin-js

round-robin-js

An implementation of the round robin as a data structure. Two strategies are implemented to select the next item in the round, a Sequential one that selects the next item based on the order of insertion, and a Random one that selects the next item randomly.

Contents

• Install
• API
  • import
  • constructor
  • add(value)
  • count()
  • next()
  • deleteByKey(key)
  • deleteByValue(cb)
  • reset()
  • clear()
• Build
• License

Install

npm install --save round-robin-js

API

import

JS

const { SequentialRoundRobin, RandomRoundRobin } = require('round-robin-js');

// OR

import { SequentialRoundRobin, RandomRoundRobin } from 'round-robin-js';

TS

import {
  SequentialRoundRobin,
  RandomRoundRobin,
  RoundRobinItem // the internal item type
} from 'round-robin-js';

constructor

accepts an initial list of values.

JS

params
values: array

const sequentialTable = new SequentialRoundRobin(['T1', 'T2', 'T3']);

const randomTable = new RandomRoundRobin([5, 10, 15]);

TS

params
values: T[]

const sequentialTable = new SequentialRoundRobin<string>(['T1', 'T2', 'T3']);

const randomTable = new RandomRoundRobin<number>([5, 10, 15]);

add(value)

adds a new item to the table.

JS

params	return
value: any	object

const { key, value } = sequentialTable.add('T4');
console.log(key, value); // 3, T4

const { key, value } = randomTable.add(25);
console.log(key, value); // 3, 25

TS

params	return
value: T	RoundRobinItem<T>

const item: RoundRobinItem = sequentialTable.add('T4');
console.log(item); // { key: 3, value: 'T4' }

const item: RoundRobinItem = randomTable.add(25);
console.log(item); // { key: 3, value: 25 }

count()

returns the number of items in the table.

return
number

console.log(sequentialTable.count()); // 4

console.log(randomTable.count()); // 4

next()

returns the next item in the round.

return
object (RoundRobinItem<T>)

// first round
console.log(sequentialTable.next()); // { key: 0, value: 'T1' }
console.log(sequentialTable.next()); // { key: 1, value: 'T2' }
console.log(sequentialTable.next()); // { key: 2, value: 'T3' }
console.log(sequentialTable.next()); // { key: 3, value: 'T4' }
// second round ...
console.log(sequentialTable.next()); // { key: 0, value: 'T1' }

// first round
console.log(randomTable.next()); // { key: 2, value: 15 }
console.log(randomTable.next()); // { key: 1, value: 10 }
console.log(randomTable.next()); // { key: 0, value: 5 }
console.log(randomTable.next()); // { key: 3, value: 25 }
// second round ...
console.log(randomTable.next()); // { key: 1, value: 10 }

deleteByKey(key)

deletes an item by its key from the table.

return
boolean

sequentialTable.deleteByKey(0);
sequentialTable.deleteByKey(2);
console.log(sequentialTable.next()); // { key: 1, value: 'T2' }
console.log(sequentialTable.next()); // { key: 3, value: 'T4' }
console.log(sequentialTable.next()); // { key: 1, value: 'T2' }

randomTable.deleteByKey(0);
randomTable.deleteByKey(2);
console.log(randomTable.next()); // { key: 3, value: 25 }
console.log(randomTable.next()); // { key: 1, value: 10 }
console.log(randomTable.next()); // { key: 3, value: 25 }

deleteByValue(cb)

deletes items with values that match a criteria from the table and returns the number of deleted items.

params	return
cb: (value: T) => boolean	number

const seqTable = new SequentialRoundRobin<number>([2, 3, 5, 6, 7, 10]);
const ranTable = new RandomRoundRobin<{ id: string }>([
  { id: '123' },
  { id: 'id456' },
  { id: '456' },
  { id: 'id780' }
]);

const d1 = seqTable.deleteByValue((n) => n % 2 === 1); // 3
console.log(seqTable.next(), seqTable.next(), seqTable.next())
// { key: 0, value: 2 } { key: 3, value: 6 } { key: 5, value: 10 }

const d2 = ranTable.deleteByValue((obj) => obj.id.indexOf('id') === 0); // 2
console.log(ranTable.next(), ranTable.next())
// { key: 2, value: { id: '456' } } { key: 0, value: { id: '123' } }

reset()

resets the table with the intial values.

sequentialTable.reset();
console.log(sequentialTable.count()); // 3

randomTable.reset();
console.log(randomTable.count()); // 3

clear()

clears all values in the table.

sequentialTable.clear();
console.log(sequentialTable.count()); // 0

randomTable.clear();
console.log(randomTable.count()); // 0

Build

grunt build

License

The MIT License. Full License is here

Changelog

[2.0.1] - 2022-feb-11

Fixed

• readme