v5.3.1

docs/_data/versions.yml

@@ -1,5 +1,5 @@
 schema: '5'
-vega: '5.3.0'
+vega: '5.3.1'
 vega-lite: '3.0.0-rc15'
 vega-embed: '4.0.0-rc1'
 d3: '5.9.2'

docs/index.md

@@ -14,6 +14,8 @@ Vega provides basic building blocks for a wide variety of visualization designs:
 
 A Vega _specification_ defines an interactive visualization in a [JSON](http://en.wikipedia.org/wiki/JSON) format. Specifications are parsed by Vega's JavaScript _runtime_ to generate both static images or interactive web-based views. Vega provides a convenient representation for computational generation of visualizations, and can serve as a foundation for new APIs and visual analysis tools.
 
-To get started with Vega, take a look at the [tutorials](tutorials), [example gallery](examples), and [usage guide](usage), or read [about the project's goals](about). To create common statistical graphics in a more concise form, check out [Vega-Lite](https://vega.github.io/vega-lite), a higher-level language built on top of Vega.
+To get started with Vega, take a look at the [tutorials](tutorials), [example gallery](examples), and [usage guide](usage), or read [about the project's goals](about).
+
+To rapidly create common statistical graphics, check out [Vega-Lite](https://vega.github.io/vega-lite), a higher-level language built on top of Vega. Not that into JavaScript? Take a look at the [Altair Python API](https://altair-viz.github.io/) for Vega-Lite.
 
 Need help or want to share examples? Join the [Vega discussion forum](https://groups.google.com/forum/#!forum/vega-js) or the [Vega Slack organization](http://bit.ly/vega-slack)!

docs/vega-core.js

@@ -3486,7 +3486,7 @@
         div  = _.divide || [5, 2],
         min  = _.extent[0],
         max  = _.extent[1],
-        span = max - min,
+        span = (max - min) || Math.abs(min) || 1,
         step, level, minstep, precision, v, i, n, eps;
 
     if (_.step) {
@@ -3528,7 +3528,7 @@
 
     return {
       start: min,
-      stop:  max,
+      stop:  max === min ? min + step : max,
       step:  step
     };
   }
@@ -17288,7 +17288,7 @@
     resolvefilter: ResolveFilter
   });
 
-  var version = "5.3.0";
+  var version = "5.3.1";
 
   var Default = 'default';
 
@@ -21885,11 +21885,8 @@
   }
 
   function mergeStream(stream, scope) {
-    var list = stream.merge.map(function(s) {
-      return parseStream$1(s, scope);
-    });
-
-    var entry = streamParameters({merge: list}, stream, scope);
+    var list = stream.merge.map(s => parseStream$1(s, scope)),
+        entry = streamParameters({merge: list}, stream, scope);
     return scope.addStream(entry).id;
   }
 
@@ -21928,7 +21925,7 @@
       ];
     }
 
-    param = stream.filter ? array(stream.filter) : [];
+    param = stream.filter ? [].concat(stream.filter) : [];
     if (stream.marktype || stream.markname || stream.markrole) {
       // add filter for mark type, name and/or role
       param.push(filterMark(stream.marktype, stream.markname, stream.markrole));