Add .polygon()

mapbox · Jul 16, 2014 · 96b936c · 96b936c
1 parent 6d3adee
commit 96b936c
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Showing 3 changed files with 36 additions and 2 deletions.
diff --git a/README.md b/README.md
@@ -2,7 +2,7 @@
 
 # extent
 
-a simple geographical extent
+A simple geographical extent.
 
 ## api
 
@@ -21,4 +21,9 @@ Expand the extent to include another extent.
 ### `extent.bbox()`
 
 Get the extent's value. `null` if no points have
-been included yet.
+been included yet. Order is `[WSEN]` to match the [GeoJSON](http://geojson.org/)
+standard.
+
+### `extent.polygon()`
+
+Get the extent as a [GeoJSON](http://geojson.org/) Polygon geometry object.
diff --git a/index.js b/index.js
@@ -30,3 +30,24 @@ Extent.prototype.bbox = function() {
     if (!this._valid) return null;
     return this._bbox;
 };
+
+Extent.prototype.polygon = function() {
+    if (!this._valid) return null;
+    return {
+        type: 'Polygon',
+        coordinates: [
+            [
+                // W, S
+                [this._bbox[0], this._bbox[1]],
+                // E, S
+                [this._bbox[2], this._bbox[1]],
+                // E, N
+                [this._bbox[2], this._bbox[3]],
+                // W, N
+                [this._bbox[0], this._bbox[3]],
+                // W, S
+                [this._bbox[0], this._bbox[1]]
+            ]
+        ]
+    };
+};
diff --git a/test/extent.js b/test/extent.js
@@ -17,5 +17,13 @@ test('extent', function(t) {
         .include([-10, -10])
         .bbox(),
             [-10, -10, 10, 10], 'three points');
+    t.deepEqual(Extent()
+        .include([0, 0])
+        .include([10, 10])
+        .include([-10, -10])
+        .polygon(), {
+            type: 'Polygon',
+            coordinates: [[[-10,-10],[10,-10],[10,10],[-10,10],[-10,-10]]]
+        }, 'polygon');
     t.end();
 });