mpanalytics/lib/hash.js

Wrapper around google analytics measurement protocol, works both client- and serverside.

// http://werxltd.com/wp/2010/05/13/
// javascript-implementation-of-javas-string-hashcode-method/
export function get(str) {
  var hash = 0;
  var len = str.length;

  if (len == 0) return hash;

  for (var i = 0; i < len; i++) {
    var c = str.charCodeAt(i);
    hash = (hash << 5) - hash + c;
    hash = hash & hash;
  }

  return hash;
}

/**
 * Calculate index for string within length based on hash.
 *
 * @returns {number} - Index within length, in range [0 -> length).
 */
export function range(str, length) {
  return Math.abs(get(str) % length);
}

export default {
  get,
  range,
};