talisman/metrics/length.js

Straightforward fuzzy matching, information retrieval and NLP building blocks for JavaScript.

"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.similarity = similarity;
exports.distance = distance;
/**
 * Talisman metrics/length
 * ========================
 *
 * Length distance/similarity. Basically just the ratio of the shorter length
 * over the longer length.
 *
 * [Tags]: metric, string metric.
 */

/**
 * Length similarity.
 *
 * @param  {array|string} a - First sequence.
 * @param  {array|string} b - Second sequence.
 */
function similarity(a, b) {
  if (a === b) return 1;

  var la = a.length,
      lb = b.length;

  if (!la || !lb) return 0;

  if (la < lb) return la / lb;

  return lb / la;
}

/**
 * Length distance.
 *
 * @param  {array|string} a - First sequence.
 * @param  {array|string} b - Second sequence.
 */
function distance(a, b) {
  return 1 - similarity(a, b);
}