Clustering.js

import chroma from 'chroma-js';

const cluster = (colors, centers) => {
  const centerCounts = {};
  for(let color of colors) {
    let bestCenter = null;
    let bestCenterDist = Number.MAX_VALUE;
    for(let center in centers) {
      const dist = chroma.distance(color, centers[center]);
      if(dist < bestCenterDist) {
        bestCenter = center;
        bestCenterDist = dist;
      }
      centerCounts[bestCenter] = (centerCounts[bestCenter] || 0) + 1;
    }
  }

  return Object.keys(centerCounts).map(center => ({center: centers[center], count: centerCounts[center]}));
}

const THRESHOLD = 30;
const groupClusters = centers => centers.slice(1).reduce((newCenters, center) => {
  let minThreshold = Number.MAX_VALUE;
  let minIdx = null;

  for(let newCenterIdx in newCenters) {
    const newCenter = newCenters[newCenterIdx];
    const dist = chroma.distance(newCenter.center, center.center)
    if(dist < minThreshold) {
      minThreshold = dist;
      minIdx = newCenterIdx;
    }
  }

  if(minThreshold < THRESHOLD) {
    const newCenter = newCenters[minIdx];
    if(newCenter.count < center.count) {
      newCenters[minIdx].center = center.center;
    }
    newCenters[minIdx].count = newCenter.count += center.count;
    console.log('Clustered', newCenter, center);
    return newCenters;
  }

  return newCenters.concat([center]);
}, [centers[0]]);

const significance = centers => {
  const sum = centers.reduce((sum, {count}) => sum+count, 0);

  return centers.map(center => Object.assign({significance: center.count/sum}, center));
}

const sort = centerCounts => centerCounts.sort(({count: countA}, {count: countB}) => countB-countA);

const filterHueless = centers => centers.filter(({center}) => {
  const hsl = center.hsl();
  console.log(center.toString(), center.name(), ...center.hsl());
  if(isNaN(hsl[0])) return false;
  return hsl[2] <= 0.80 && hsl[2] >= 0.2 && hsl[1] >= 0.05;
});