reductio/src/histogram.js

Reductio: Crossfilter groupings

import crossfilter from 'crossfilter2';

var histogram = {
	add: function (a, prior, path) {
		var bisect = crossfilter.bisect.by(function(d) { return d; }).left;
		var bisectHisto = crossfilter.bisect.by(function(d) { return d.x; }).right;
		var curr;
		return function (p, v, nf) {
			if(prior) prior(p, v, nf);
			curr = path(p).histogram[bisectHisto(path(p).histogram, a(v), 0, path(p).histogram.length) - 1];
			curr.y++;
			curr.splice(bisect(curr, a(v), 0, curr.length), 0, a(v));
			return p;
		};
	},
	remove: function (a, prior, path) {
		var bisect = crossfilter.bisect.by(function(d) { return d; }).left;
		var bisectHisto = crossfilter.bisect.by(function(d) { return d.x; }).right;
		var curr;
		return function (p, v, nf) {
			if(prior) prior(p, v, nf);
			curr = path(p).histogram[bisectHisto(path(p).histogram, a(v), 0, path(p).histogram.length) - 1];
			curr.y--;
			curr.splice(bisect(curr, a(v), 0, curr.length), 1);
			return p;
		};
	},
	initial: function (thresholds, prior, path) {
		return function (p) {
			p = prior(p);
			path(p).histogram = [];
			var arr = [];
			for(var i = 1; i < thresholds.length; i++) {
				arr = [];
				arr.x = thresholds[i - 1];
				arr.dx = (thresholds[i] - thresholds[i - 1]);
				arr.y = 0;
				path(p).histogram.push(arr);
			}
			return p;
		};
	}
};

export default histogram;