engineN/public/theme/plugins/d3-scale/src/sequential.js

import {linearish} from "./linear";

export default function sequential(interpolator) {
  var x0 = 0,
      x1 = 1,
      k10 = 1,
      clamp = false;

  function scale(x) {
    var t = (x - x0) * k10;
    return interpolator(clamp ? Math.max(0, Math.min(1, t)) : t);
  }

  scale.domain = function(_) {
    return arguments.length ? (x0 = +_[0], x1 = +_[1], k10 = x0 === x1 ? 0 : 1 / (x1 - x0), scale) : [x0, x1];
  };

  scale.clamp = function(_) {
    return arguments.length ? (clamp = !!_, scale) : clamp;
  };

  scale.interpolator = function(_) {
    return arguments.length ? (interpolator = _, scale) : interpolator;
  };

  scale.copy = function() {
    return sequential(interpolator).domain([x0, x1]).clamp(clamp);
  };

  return linearish(scale);
}