Refactor basic plugins with visitor api (#1518)

- cleanupAttrs
- convertEllipseToCircle
- removeDesc
- removeDoctype
- removeEmptyText
- removeMetadata
- removeRasterImages
- removeScriptElement
- removeStyleElement
- removeTitle
- removeXMLProcInst

plugins/convertEllipseToCircle.js

@@ -1,9 +1,7 @@
 'use strict';
 
-exports.type = 'perItem';
-
+exports.type = 'visitor';
 exports.active = true;
-
 exports.description = 'converts non-eccentric <ellipse>s to <circle>s';
 
 /**
@@ -11,26 +9,28 @@ exports.description = 'converts non-eccentric <ellipse>s to <circle>s';
  *
  * @see https://www.w3.org/TR/SVG11/shapes.html
  *
- * @param {Object} item current iteration item
- * @return {Boolean} if false, item will be filtered out
- *
  * @author Taylor Hunt
  */
-exports.fn = function (item) {
-  if (item.isElem('ellipse')) {
-    const rx = item.attributes.rx || 0;
-    const ry = item.attributes.ry || 0;
-
-    if (
-      rx === ry ||
-      rx === 'auto' ||
-      ry === 'auto' // SVG2
-    ) {
-      var radius = rx !== 'auto' ? rx : ry;
-      item.renameElem('circle');
-      delete item.attributes.rx;
-      delete item.attributes.ry;
-      item.attributes.r = radius;
-    }
-  }
+exports.fn = () => {
+  return {
+    element: {
+      enter: (node) => {
+        if (node.name === 'ellipse') {
+          const rx = node.attributes.rx || 0;
+          const ry = node.attributes.ry || 0;
+          if (
+            rx === ry ||
+            rx === 'auto' ||
+            ry === 'auto' // SVG2
+          ) {
+            node.name = 'circle';
+            const radius = rx === 'auto' ? ry : rx;
+            delete node.attributes.rx;
+            delete node.attributes.ry;
+            node.attributes.r = radius;
+          }
+        }
+      },
+    },
+  };
 };