overpass-frontend/src/qlFunctions/around.js

A JavaScript (NodeJS/Browser) library to easily access data from OpenStreetMap via Overpass API or from an OSM File. The objects can directly be used with LeafletJS or exported to GeoJSON. Data will be cached in the browser memory.

const turf = require('../turf')
const arrayToCoords = require('../arrayToCoords')
const OverpassFrontend = require('../defines')
const qlFunction = require('./qlFunction')

module.exports = class around extends qlFunction {
  constructor (str) {
    super()
    this.fun = 'around'
    const s = str.split(/,/g)

    if (s.length < 3) {
      throw new Error('around function expects "distance,latitude,longitude[,latitude,longitude[,...]]"')
    } else if (s.length === 3) {
      this.value = { distance: parseFloat(s[0]), geometry: { type: 'Point', coordinates: [parseFloat(s[2]), parseFloat(s[1])] } }
    } else if (s.length % 2 === 1) {
      this.value = { distance: parseFloat(s[0]), geometry: { type: 'LineString', coordinates: arrayToCoords(s.slice(1).map(v => parseFloat(v))) } }
    } else {
      throw new Error('around function expects "distance,latitude,longitude[,latitude,longitude[,...]]"')
    }
  }

  test (ob) {
    return ob.intersects(this.bounds())
  }

  toString () {
    return '(around:' + this.value.distance + ',' + this.value.geometry.coordinates[1] + ',' + this.value.geometry.coordinates[0] + ')'
  }

  compileLokiJS () {
    return { needMatch: true }
  }

  cacheDescriptors (descriptors) {
    const bounds = this.bounds()

    descriptors.forEach(d => {
      const newBounds = d.bounds ? turf.intersect(d.bounds, bounds) : bounds
      if (newBounds === null) {
        d.invalid = true
      } else {
        d.bounds = newBounds.geometry
        d.properties |= OverpassFrontend.GEOM
      }
    })
  }

  isSupersetOf (other) {
    if (other instanceof around && this.value.geometry.type === 'Point' && other.value.geometry.type === 'Point') {
      const distance = turf.distance(this.value.geometry, other.value.geometry, 'kilometers') * 1000
      return distance < this.value.distance - other.value.distance
    }

    if (other.bounds) {
      return !!turf.difference(this.bounds(), other.bounds())
    }
  }

  bounds () {
    if (!this._bounds) {
      this._bounds = turf.buffer(this.value.geometry, this.value.distance / 1000, { units: 'kilometers' })
    }

    return this._bounds
  }
}