get-epsg-code/lib/hash.js

Gets EPSG Code for Various Inputs (incl. OGC WKT, ESRI WKT, GML, Mapfile, PROJ String, Proj4js String, XML)

function hash32(string) {
  // sometimes might have extra space at end from epsg.io
  string = string.trim();

  // replace new lines with spaces
  string = string.replace(/\n/g, " ");

  // replace tabs with spaces
  string = string.replace(/\t/g, " ");

  // remove any extra spaces
  string = string.replace(/ +/g, " ");

  let hash = 0;
  let i;
  let chr;
  if (string.length === 0) return hash;
  const string_length = string.length;
  for (i = 0; i < string_length; i++) {
    chr = string.charCodeAt(i);
    hash = (hash << 5) - hash + chr;
    hash |= 0; // Convert to 32bit integer
  }

  // convert to 16-bit
  // hash = Math.round(hash / Math.pow(2, 16));

  return hash;
}

module.exports = hash32;
module.exports.default = hash32;