vis-utils/lib/findClosestUnsorted.js

Utility functions for data visualization

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.default = findClosestUnsorted;
/**
 * Helper function to compute distance and find the closest item
 * Since it assumes the data is unsorted, it does a linear scan O(n).
 *
 * @param {Array} array the input array to search
 * @param {Number} value the value to match against (typically pixels)
 * @param {Function} accessor applied to each item in the array to get equivalent
 *   value to compare against
 * @return {Any} The item in the array that is closest to `value`
 */
function findClosestUnsorted(array, value) {
  var accessor = arguments.length > 2 && arguments[2] !== undefined ? arguments[2] : function (d) {
    return d;
  };

  var closest = null;
  var closestDist = null;

  array.forEach(function (elem) {
    var dist = Math.abs(accessor(elem) - value);
    if (closestDist == null || dist < closestDist) {
      closestDist = dist;
      closest = elem;
    }
  });

  return closest;
}