Add minzoom check to map.zoom() (closes #2499)

js/id/renderer/map.js

@@ -326,6 +326,13 @@ iD.Map = function(context) {
             return Math.max(Math.log(projection.scale() * 2 * Math.PI) / Math.LN2 - 8, 0);
         }
 
+        if (z < minzoom) {
+            iD.ui.flash(context.container())
+                .select('.content')
+                .text(t('cannot_zoom'));
+            z = context.minEditableZoom();
+        }
+
         if (setZoom(z)) {
             dispatch.move(map);
         }

test/spec/renderer/map.js

@@ -30,6 +30,12 @@ describe('iD.Map', function() {
             map.zoom(4);
             expect(spy).not.to.have.been.called;
         });
+
+        it('respects minzoom', function() {
+            map.minzoom(16);
+            map.zoom(15);
+            expect(map.zoom()).to.equal(16);
+        });
     });
 
     describe('#zoomIn', function() {