GetType and GetCoords implementation (#44)

README.md

@@ -122,7 +122,7 @@ Turf for Go is a ported library in GoLang ported from the Turf.js library.
 - [ ] clustersDbscan
 - [ ] clustersKmeans
 
-## Meta
+## Meta - Invariant
 - [x] coordAll
 - [x] coordEach
 - [ ] coordReduce
@@ -131,9 +131,9 @@ Turf for Go is a ported library in GoLang ported from the Turf.js library.
 - [ ] flattenEach
 - [ ] flattenReduce
 - [x] getCoord
-- [ ] getCoords
+- [x] getCoords
 - [ ] getGeom
-- [ ] getType
+- [x] getType
 - [ ] geomEach
 - [ ] geomReduce
 - [ ] propEach

geojson/feature/feature.go

@@ -222,7 +222,7 @@ func (f *Feature) ToLineString() (*geometry.LineString, error) {
 
 // ToMultiLineString converts a MultiLineString faeture to MultiLineString geometry.
 func (f *Feature) ToMultiLineString() (*geometry.MultiLineString, error) {
-	if f.Geometry.GeoJSONType != geojson.MiltiLineString {
+	if f.Geometry.GeoJSONType != geojson.MultiLineString {
 		return nil, errors.New("invalid geometry type")
 	}
 	var coords [][][]float64

geojson/geometry/geometry.go

@@ -198,7 +198,7 @@ func (g *Geometry) ToLineString() (*LineString, error) {
 
 // ToMultiLineString converts a MultiLineString faeture to MultiLineString geometry.
 func (g *Geometry) ToMultiLineString() (*MultiLineString, error) {
-	if g.GeoJSONType != geojson.MiltiLineString {
+	if g.GeoJSONType != geojson.MultiLineString {
 		return nil, errors.New("invalid geometry type")
 	}
 	var coords [][][]float64

geojson/type.go

@@ -10,8 +10,8 @@ const (
 	MultiPoint OBjectType = "MultiPoint"
 	// LineString Defines a LineString Type https://tools.ietf.org/html/rfc7946#section-3.1.4
 	LineString OBjectType = "LineString"
-	// MiltiLineString Defines a MultiLineString Type https://tools.ietf.org/html/rfc7946#section-3.1.5
-	MiltiLineString OBjectType = "MultiLineString"
+	// MultiLineString Defines a MultiLineString Type https://tools.ietf.org/html/rfc7946#section-3.1.5
+	MultiLineString OBjectType = "MultiLineString"
 	// Polygon Defines a Polygon Type https://tools.ietf.org/html/rfc7946#section-3.1.6
 	Polygon OBjectType = "Polygon"
 	// MultiPolygon Defines a MultiPolygon Type https://tools.ietf.org/html/rfc7946#section-3.1.7

invariant/invariant.go

@@ -69,3 +69,144 @@ func GetCoord(coord interface{}) ([]float64, error) {
 
 	return nil, errors.New("coord must be GeoJSON Point or an Array of numbers")
 }
+
+// GetCoords unwrap coordinates from a Feature, Geometry, Object or an Array
+//
+// Example:
+//
+// coords: &geometry.Point{
+//	  Lat: 23.52,
+//	  Lng: 44.34,
+//  },
+//
+// coords,err := GetCoords(coords)
+// = []float64{44.34, 23.52}
+//
+func GetCoords(coords interface{}) (interface{}, error) {
+	if coords == nil {
+		return nil, errors.New("coord is required")
+	}
+	switch gtp := coords.(type) {
+	case *feature.Feature: // Feature
+		if gtp.Type == geojson.Feature {
+			switch gtp.Geometry.GeoJSONType {
+			case geojson.Point:
+				_, err := gtp.Geometry.ToPoint()
+				if err != nil {
+					return nil, err
+				}
+				return gtp.Geometry.Coordinates, nil
+			case geojson.MultiPoint:
+				_, err := gtp.Geometry.ToMultiPoint()
+				if err != nil {
+					return nil, err
+				}
+				return gtp.Geometry.Coordinates, nil
+			case geojson.LineString:
+				_, err := gtp.Geometry.ToLineString()
+				if err != nil {
+					return nil, err
+				}
+				return gtp.Geometry.Coordinates, nil
+			case geojson.Polygon:
+				_, err := gtp.Geometry.ToPolygon()
+				if err != nil {
+					return nil, err
+				}
+				return gtp.Geometry.Coordinates, nil
+			case geojson.MultiLineString:
+				_, err := gtp.Geometry.ToMultiLineString()
+				if err != nil {
+					return nil, err
+				}
+				return gtp.Geometry.Coordinates, nil
+			case geojson.MultiPolygon:
+				_, err := gtp.Geometry.ToMultiPolygon()
+				if err != nil {
+					return nil, err
+				}
+				return gtp.Geometry.Coordinates, nil
+			}
+		}
+	// Geometry
+	case *geometry.Polygon:
+		result := [][][]float64{}
+		for i := 0; i < len(gtp.Coordinates); i++ {
+			coords := [][]float64{}
+			for j := 0; j < len(gtp.Coordinates[i].Coordinates); j++ {
+				coords = append(coords, []float64{gtp.Coordinates[i].Coordinates[j].Lng, gtp.Coordinates[i].Coordinates[j].Lat})
+			}
+			result = append(result, coords)
+		}
+		return result, nil
+	case *geometry.LineString:
+		result := [][]float64{}
+		for i := 0; i < len(gtp.Coordinates); i++ {
+			result = append(result, []float64{gtp.Coordinates[i].Lng, gtp.Coordinates[i].Lat})
+		}
+		return result, nil
+	case *geometry.MultiLineString:
+		result := [][][]float64{}
+		for i := 0; i < len(gtp.Coordinates); i++ {
+			tmp := [][]float64{}
+			for j := 0; j < len(gtp.Coordinates[i].Coordinates); j++ {
+				tmp = append(tmp, []float64{gtp.Coordinates[i].Coordinates[j].Lng, gtp.Coordinates[i].Coordinates[j].Lat})
+			}
+			result = append(result, tmp)
+		}
+		return result, nil
+	case *geometry.Point:
+		result := []float64{}
+		result = append(result, gtp.Lng, gtp.Lat)
+		return result, nil
+	case *geometry.MultiPoint:
+		result := [][]float64{}
+		for i := 0; i < len(gtp.Coordinates); i++ {
+			tmp := []float64{}
+			tmp = append(tmp, gtp.Coordinates[i].Lng, gtp.Coordinates[i].Lat)
+			result = append(result, tmp)
+		}
+		return result, nil
+	case *geometry.MultiPolygon:
+		result := [][][][]float64{}
+		for i := 0; i < len(gtp.Coordinates); i++ {
+			tmp := [][][]float64{}
+			for j := 0; j < len(gtp.Coordinates[i].Coordinates); j++ {
+				tmPoly := [][]float64{}
+				for k := 0; k < len(gtp.Coordinates[i].Coordinates[j].Coordinates); k++ {
+					tmPoly = append(tmPoly, []float64{gtp.Coordinates[i].Coordinates[j].Coordinates[k].Lng, gtp.Coordinates[i].Coordinates[j].Coordinates[k].Lat})
+				}
+				tmp = append(tmp, tmPoly)
+			}
+			result = append(result, tmp)
+		}
+		return result, nil
+	case []float64:
+		if utils.IsArray(gtp) && len(gtp) >= 2 {
+			return gtp, nil
+		}
+	}
+	return nil, errors.New("coord must be GeoJSON Point or an Array of numbers")
+}
+
+// GetType returns the GeoJSON object's type
+//
+// Examples:
+//
+// fp, err := feature.FromJSON("{ \"type\": \"Feature\", \"properties\": {}, \"geometry\": { \"type\": \"Point\", \"coordinates\": [102, 0.5] } }")
+// result := GetType(fp)
+// ="Point"
+//
+func GetType(geojson interface{}) string {
+	switch gtp := geojson.(type) {
+	case *feature.Feature:
+		return string(gtp.Geometry.GeoJSONType)
+	case *feature.Collection:
+		return string(gtp.Type)
+	case *geometry.Collection:
+		return string(gtp.Type)
+	case *geometry.Geometry:
+		return string(gtp.GeoJSONType)
+	}
+	return "invalid"
+}