highest-averages

Zero-dependency and extensible set of highest averages methods for allocating seats in a parliament.

Install

npm i highest-averages

Pure Example

• Define the candidates with their vote

const a = new Candidate('A', 200)
const b = new Candidate('B', 140)
const c = new Candidate('C', 70)

• Implement divisor function

const divisor: Divisor = new class implements Divisor {
  next (iteration: number): number {
    return iteration + 2
  }
}

• Define the highest averages method

const highestAverage = new HighestAverage(divisor)

• Get the results for 5 seats

const result = highestAverage
  .withSeat(5)
  .withCandidates([a, b, c])
  .apply()

result.forEach(candidate => console.log(`${candidate.name()}:${candidate.seat}`))

• Result

A:3
B:2
C:0

• Selection table of example

| | 1 | 2 | 3 | 4 | 5 | Result | |---|------|-------|--------|-------|--------|--------| | A | 100* | 66.66 | 66.66* | 50* | 40 | 3 | | B | 70 | 70* | 46.66 | 46.66 | 46.66* | 2 | | C | 35 | 35 | 35 | 35 | 35 | 0 |

Predefined Highest Averages Methods

• D'Hondt

const result = new DHondt()
  .withSeat(5)
  .withCandidates([])
  .apply()

• Sainte-Laguë

const result = new SainteLague()
  .withSeat(5)
  .withCandidates([])
  .apply()

• Imperiali

const result = new Imperiali()
  .withSeat(5)
  .withCandidates([])
  .apply()

• Huntington–Hill

const result = new HuntingtonHill()
  .withSeat(5)
  .withCandidates([])
  .apply()

• Danish

const result = new Danish()
  .withSeat(5)
  .withCandidates([])
  .apply()

Election Implementations (examples)

• Greenland general election (Inatsisartut) (2018, 2021)
• Dutch general election (Tweede Kamer der Staten-Generaal) (2017, 2021)
• San Marino general election (Consiglio Grande e Generale) (2019)