Simplify.

d3.js

@@ -5495,38 +5495,18 @@
     function circle() {
       var o = typeof origin === "function" ? origin.apply(this, arguments) : origin;
       rotate = d3_geo_rotation(-o[0] * d3_radians, -o[1] * d3_radians, 0);
-      var rings = [ [] ], context = bufferContext(rings);
-      d3_geo_circleInterpolateCircle(interpolate, context);
-      context.closePath();
-      return {
-        type: "Polygon",
-        coordinates: rings
-      };
-    }
-    function bufferContext(rings) {
-      var ring = rings[0];
-      return {
-        point: function(λ, φ) {
-          var point = rotate.invert(λ, φ);
-          point[0] *= d3_degrees;
-          point[1] *= d3_degrees;
-          rings.push(point);
-        },
-        moveTo: function(λ, φ) {
-          var point = rotate.invert(λ, φ);
-          point[0] *= d3_degrees;
-          point[1] *= d3_degrees;
-          rings.push(ring = [ point ]);
-        },
+      var ring = [];
+      d3_geo_circleInterpolateCircle(interpolate, {
         lineTo: function(λ, φ) {
           var point = rotate.invert(λ, φ);
           point[0] *= d3_degrees;
           point[1] *= d3_degrees;
           ring.push(point);
-        },
-        closePath: function() {
-          if (ring.length) ring.push(ring[0]);
         }
+      });
+      return {
+        type: "Polygon",
+        coordinates: [ ring ]
       };
     }
     circle.origin = function(x) {

src/geo/circle.js

@@ -8,39 +8,18 @@ d3.geo.circle = function() {
   function circle() {
     var o = typeof origin === "function" ? origin.apply(this, arguments) : origin;
     rotate = d3_geo_rotation(-o[0] * d3_radians, -o[1] * d3_radians, 0);
-    var rings = [[]], context = bufferContext(rings);
-    d3_geo_circleInterpolateCircle(interpolate, context);
-    context.closePath();
-    return {
-      type: "Polygon",
-      coordinates: rings
-    };
-  }
-
-  function bufferContext(rings) {
-    var ring = rings[0];
-    return {
-      point: function(λ, φ) {
-        var point = rotate.invert(λ, φ);
-        point[0] *= d3_degrees;
-        point[1] *= d3_degrees;
-        rings.push(point);
-      },
-      moveTo: function(λ, φ) {
-        var point = rotate.invert(λ, φ);
-        point[0] *= d3_degrees;
-        point[1] *= d3_degrees;
-        rings.push(ring = [point]);
-      },
+    var ring = [];
+    d3_geo_circleInterpolateCircle(interpolate, {
       lineTo: function(λ, φ) {
         var point = rotate.invert(λ, φ);
         point[0] *= d3_degrees;
         point[1] *= d3_degrees;
         ring.push(point);
-      },
-      closePath: function() {
-        if (ring.length) ring.push(ring[0]);
       }
+    });
+    return {
+      type: "Polygon",
+      coordinates: [ring]
     };
   }