D'Hondt

D'Hondt is a utility that computes election results and outputs number of mandates each party received. See D'Hondt method wiki page for details on how the D'Hondt algorithm works. ##API dhondt.compute(votes, mandates [, options])

• votes is an array of how many votes each party has received or an array of object if you specify options.voteAccessor function (see examples)
• mandates is an integer, how many mandates are being allocated
• options object can have following properties:
  • voteAccessor: function returning the number of votes from an object
  • resultProperty: if array of objects is passed, specifies which property of the object should house the result. If not specified, array of mandates is returned
  • base: Specifies the base divider used in first round of mandate allocation. Sometimes 1.42 is used to favor large parties is smaller districts.

Examples

var dhondt = require ('dhondt')
var votes = [100000, 80000, 30000, 20000];
var mandates = 8;
var results = dhondt.compute(votes, mandates);
console.log(results);
// [ 4, 3, 1, 0 ]

var parties = [
    {party: "A", votes: 100},
    {party: "B", votes:  60},
    {party: "C", votes:  45}
];
var mandates = 2;
options = {
    voteAccessor: function(object) {return object.votes},
    resultProperty: "mandates",
    base: 1.42
}
var results = dhondt.compute(parties, mandates, options);
console.log(results);
// [ { party: 'A', votes: 100, mandates: 2 },
//   { party: 'B', votes: 60, mandates: 0 },
//   { party: 'C', votes: 45, mandates: 0 } ]

Licence (MIT)

Copyright (c) 2013 Economia, a.s.

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