featureserver/lib/helpers/get-collection-crs.js

*An open source implementation of the GeoServices specification*

const _ = require('lodash')
const OGC_WGS84 = 'ogc:1.3:crs84'

function getCollectionCrs (collection) {
  const collectionCrs = _.get(collection, 'crs.properties.name')
  if (!collectionCrs) return

  const crs = collectionCrs.toLowerCase().replace(/urn:ogc:def:crs:/, '')
  if (crs === OGC_WGS84) return

  const crsRegex = /(?<authority>[a-z]+)(::|:)(?<srid>.+)/
  const result = crsRegex.exec(crs)
  if (!result) return
  const { groups: { srid } } = result
  return srid
}

module.exports = getCollectionCrs