winnow/lib/sql-query-builder/select/geometry-select-fragment.js

Apply sql-like filters to GeoJSON

const isDifferentCrs = require('../is-different-crs')
function createGeometrySelectFragment ({ inputCrs, outputCrs, geometryPrecision, toEsri } = {}) {
  const geometryFunctions = []
  if (isDifferentCrs(inputCrs, outputCrs)) geometryFunctions.push('project($,?,?)')
  if (geometryPrecision) geometryFunctions.push('reducePrecision($,?)')
  if (toEsri) geometryFunctions.push('esriGeometry($)')

  if (geometryFunctions.length === 0) return 'geometry'

  const inlineGeometryFunctions = geometryFunctions.reduce(nestGeometryFunctions, '')
  return `${inlineGeometryFunctions} as geometry`
}

function nestGeometryFunctions (nestedFunctionString, functionString, index) {
  if (index === 0) {
    return functionString.replace('$', 'geometry')
  }
  return functionString.replace('$', nestedFunctionString)
}

module.exports = createGeometrySelectFragment