index.js

var esc = require('./lib/xml-escape')
var strxml = require('./lib/strxml'),
  tag = strxml.tag

module.exports = function tokml(geojson, options) {
  options = options || {
    documentName: undefined,
    documentDescription: undefined,
    name: 'name',
    description: 'description',
    simplestyle: false,
    timestamp: 'timestamp'
  }

  return (
    '<?xml version="1.0" encoding="UTF-8"?>' +
    tag(
      'kml',
      { xmlns: 'http://www.opengis.net/kml/2.2' },
      tag(
        'Document',
        documentName(options) +
          documentDescription(options) +
          root(geojson, options)
      )
    )
  )
}

function feature(options, styleHashesArray) {
  return function (_) {
    if (!_.properties || !geometry.valid(_.geometry)) return ''
    var geometryString = geometry.any(_.geometry)
    if (!geometryString) return ''

    var styleDefinition = '',
      styleReference = ''
    if (options.simplestyle) {
      var styleHash = hashStyle(_.properties)
      if (styleHash) {
        if (geometry.isPoint(_.geometry) && hasMarkerStyle(_.properties)) {
          if (styleHashesArray.indexOf(styleHash) === -1) {
            styleDefinition = markerStyle(_.properties, styleHash)
            styleHashesArray.push(styleHash)
          }
          styleReference = tag('styleUrl', '#' + styleHash)
          removeMarkerStyle(_.properties)
        } else if (
          (geometry.isPolygon(_.geometry) || geometry.isLine(_.geometry)) &&
          hasPolygonAndLineStyle(_.properties)
        ) {
          if (styleHashesArray.indexOf(styleHash) === -1) {
            styleDefinition = polygonAndLineStyle(_.properties, styleHash)
            styleHashesArray.push(styleHash)
          }
          styleReference = tag('styleUrl', '#' + styleHash)
          removePolygonAndLineStyle(_.properties)
        }
        // Note that style of GeometryCollection / MultiGeometry is not supported
      }
    }

    var attributes = {}
    if (_.id) attributes.id = _.id.toString();
    return (
      styleDefinition +
      tag(
        'Placemark',
        attributes,
        name(_.properties, options) +
          description(_.properties, options) +
          extendeddata(_.properties) +
          timestamp(_.properties, options) +
          geometryString +
          styleReference
      )
    )
  }
}

function root(_, options) {
  if (!_.type) return ''
  var styleHashesArray = []

  switch (_.type) {
    case 'FeatureCollection':
      if (!_.features) return ''
      return _.features.map(feature(options, styleHashesArray)).join('')
    case 'Feature':
      return feature(options, styleHashesArray)(_)
    default:
      return feature(
        options,
        styleHashesArray
      )({
        type: 'Feature',
        geometry: _,
        properties: {}
      })
  }
}

function documentName(options) {
  return options.documentName !== undefined
    ? tag('name', options.documentName)
    : ''
}

function documentDescription(options) {
  return options.documentDescription !== undefined
    ? tag('description', options.documentDescription)
    : ''
}

function name(_, options) {
  return _[options.name] ? tag('name', esc(_[options.name])) : ''
}

function description(_, options) {
  return _[options.description]
    ? tag('description', esc(_[options.description]))
    : ''
}

function timestamp(_, options) {
  return _[options.timestamp]
    ? tag('TimeStamp', tag('when', esc(_[options.timestamp])))
    : ''
}

// ## Geometry Types
//
// https://developers.google.com/kml/documentation/kmlreference#geometry
var geometry = {
  Point: function (_) {
    return tag('Point', tag('coordinates', _.coordinates.join(',')))
  },
  LineString: function (_) {
    return tag('LineString', tag('coordinates', linearring(_.coordinates)))
  },
  Polygon: function (_) {
    if (!_.coordinates.length) return ''
    var outer = _.coordinates[0],
      inner = _.coordinates.slice(1),
      outerRing = tag(
        'outerBoundaryIs',
        tag('LinearRing', tag('coordinates', linearring(outer)))
      ),
      innerRings = inner
        .map(function (i) {
          return tag(
            'innerBoundaryIs',
            tag('LinearRing', tag('coordinates', linearring(i)))
          )
        })
        .join('')
    return tag('Polygon', outerRing + innerRings)
  },
  MultiPoint: function (_) {
    if (!_.coordinates.length) return ''
    return tag(
      'MultiGeometry',
      _.coordinates
        .map(function (c) {
          return geometry.Point({ coordinates: c })
        })
        .join('')
    )
  },
  MultiPolygon: function (_) {
    if (!_.coordinates.length) return ''
    return tag(
      'MultiGeometry',
      _.coordinates
        .map(function (c) {
          return geometry.Polygon({ coordinates: c })
        })
        .join('')
    )
  },
  MultiLineString: function (_) {
    if (!_.coordinates.length) return ''
    return tag(
      'MultiGeometry',
      _.coordinates
        .map(function (c) {
          return geometry.LineString({ coordinates: c })
        })
        .join('')
    )
  },
  GeometryCollection: function (_) {
    return tag('MultiGeometry', _.geometries.map(geometry.any).join(''))
  },
  valid: function (_) {
    return (
      _ &&
      _.type &&
      (_.coordinates ||
        (_.type === 'GeometryCollection' &&
          _.geometries &&
          _.geometries.every(geometry.valid)))
    )
  },
  any: function (_) {
    if (geometry[_.type]) {
      return geometry[_.type](_)
    } else {
      return ''
    }
  },
  isPoint: function (_) {
    return _.type === 'Point' || _.type === 'MultiPoint'
  },
  isPolygon: function (_) {
    return _.type === 'Polygon' || _.type === 'MultiPolygon'
  },
  isLine: function (_) {
    return _.type === 'LineString' || _.type === 'MultiLineString'
  }
}

function linearring(_) {
  return _.map(function (cds) {
    return cds.join(',')
  }).join(' ')
}

// ## Data
function extendeddata(_) {
  return tag('ExtendedData', {}, pairs(_).map(data).join(''))
}

function data(_) {
  return tag(
    'Data',
    { name: _[0] },
    tag('value', {}, esc(_[1] ? _[1].toString() : ''))
  )
}

// ## Marker style
function hasMarkerStyle(_) {
  return !!(_['marker-size'] || _['marker-symbol'] || _['marker-color'])
}

function removeMarkerStyle(_) {
  delete _['marker-size']
  delete _['marker-symbol']
  delete _['marker-color']
  delete _['marker-shape']
}

function markerStyle(_, styleHash) {
  return tag(
    'Style',
    { id: styleHash },
    tag('IconStyle', tag('Icon', tag('href', iconUrl(_)))) + iconSize(_)
  )
}

function iconUrl(_) {
  var size = _['marker-size'] || 'medium',
    symbol = _['marker-symbol'] ? '-' + _['marker-symbol'] : '',
    color = (_['marker-color'] || '7e7e7e').replace('#', '')

  return (
    'https://api.tiles.mapbox.com/v3/marker/' +
    'pin-' +
    size.charAt(0) +
    symbol +
    '+' +
    color +
    '.png'
  )
}

function iconSize(_) {
  return tag(
    'hotSpot',
    {
      xunits: 'fraction',
      yunits: 'fraction',
      x: '0.5',
      y: '0.5'
    },
    ''
  )
}

// ## Polygon and Line style
function hasPolygonAndLineStyle(_) {
  for (var key in _) {
    if (
      {
        stroke: true,
        'stroke-opacity': true,
        'stroke-width': true,
        fill: true,
        'fill-opacity': true
      }[key]
    )
      return true
  }
}

function removePolygonAndLineStyle(_) {
  delete _['stroke']
  delete _['stroke-opacity']
  delete _['stroke-width']
  delete _['fill']
  delete _['fill-opacity']
}

function polygonAndLineStyle(_, styleHash) {
  var lineStyle = tag(
    'LineStyle',
    tag(
      'color',
      hexToKmlColor(_['stroke'], _['stroke-opacity']) || 'ff555555'
    ) +
      tag('width', {}, _['stroke-width'] === undefined ? 2 : _['stroke-width'])
  )

  var polyStyle = ''

  if (_['fill'] || _['fill-opacity']) {
    polyStyle = tag(
      'PolyStyle',
      tag(
        'color',
        {},
        hexToKmlColor(_['fill'], _['fill-opacity']) || '88555555'
      )
    )
  }

  return tag('Style', { id: styleHash }, lineStyle + polyStyle)
}

// ## Style helpers
function hashStyle(_) {
  var hash = ''

  if (_['marker-symbol']) hash = hash + 'ms' + _['marker-symbol']
  if (_['marker-color']) hash = hash + 'mc' + _['marker-color'].replace('#', '')
  if (_['marker-size']) hash = hash + 'ms' + _['marker-size']
  if (_['stroke']) hash = hash + 's' + _['stroke'].replace('#', '')
  if (_['stroke-width'])
    hash = hash + 'sw' + _['stroke-width'].toString().replace('.', '')
  if (_['stroke-opacity'])
    hash = hash + 'mo' + _['stroke-opacity'].toString().replace('.', '')
  if (_['fill']) hash = hash + 'f' + _['fill'].replace('#', '')
  if (_['fill-opacity'])
    hash = hash + 'fo' + _['fill-opacity'].toString().replace('.', '')

  return hash
}

function hexToKmlColor(hexColor, opacity) {
  if (typeof hexColor !== 'string') return ''

  hexColor = hexColor.replace('#', '').toLowerCase()

  if (hexColor.length === 3) {
    hexColor =
      hexColor[0] +
      hexColor[0] +
      hexColor[1] +
      hexColor[1] +
      hexColor[2] +
      hexColor[2]
  } else if (hexColor.length !== 6) {
    return ''
  }

  var r = hexColor[0] + hexColor[1]
  var g = hexColor[2] + hexColor[3]
  var b = hexColor[4] + hexColor[5]

  var o = 'ff'
  if (typeof opacity === 'number' && opacity >= 0.0 && opacity <= 1.0) {
    o = (opacity * 255).toString(16)
    if (o.indexOf('.') > -1) o = o.substr(0, o.indexOf('.'))
    if (o.length < 2) o = '0' + o
  }

  return o + b + g + r
}

// ## General helpers
function pairs(_) {
  var o = []
  for (var i in _) {
    if (_[i]) {
      o.push([i, _[i]])
    } else {
      o.push([i, ''])
    }
  }
  return o
}