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backend/node_modules/svgo/plugins/cleanupEnableBackground.js

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+'use strict';
+
+const csstree = require('css-tree');
+const { visit } = require('../lib/xast.js');
+
+exports.name = 'cleanupEnableBackground';
+exports.description =
+  'remove or cleanup enable-background attribute when possible';
+
+const regEnableBackground =
+  /^new\s0\s0\s([-+]?\d*\.?\d+([eE][-+]?\d+)?)\s([-+]?\d*\.?\d+([eE][-+]?\d+)?)$/;
+
+/**
+ * Remove or cleanup enable-background attr which coincides with a width/height box.
+ *
+ * @see https://www.w3.org/TR/SVG11/filters.html#EnableBackgroundProperty
+ * @example
+ * <svg width="100" height="50" enable-background="new 0 0 100 50">
+ *             ⬇
+ * <svg width="100" height="50">
+ * @author Kir Belevich
+ * @type {import('./plugins-types').Plugin<'cleanupEnableBackground'>}
+ */
+exports.fn = (root) => {
+  let hasFilter = false;
+
+  visit(root, {
+    element: {
+      enter: (node) => {
+        if (node.name === 'filter') {
+          hasFilter = true;
+        }
+      },
+    },
+  });
+
+  return {
+    element: {
+      enter: (node) => {
+        /** @type {?csstree.CssNode} */
+        let newStyle = null;
+        /** @type {?csstree.ListItem<csstree.CssNode>} */
+        let enableBackgroundDeclaration = null;
+
+        if (node.attributes.style != null) {
+          newStyle = csstree.parse(node.attributes.style, {
+            context: 'declarationList',
+          });
+
+          if (newStyle.type === 'DeclarationList') {
+            /** @type {csstree.ListItem<csstree.CssNode>[]} */
+            const enableBackgroundDeclarations = [];
+
+            csstree.walk(newStyle, (node, nodeItem) => {
+              if (
+                node.type === 'Declaration' &&
+                node.property === 'enable-background'
+              ) {
+                enableBackgroundDeclarations.push(nodeItem);
+                enableBackgroundDeclaration = nodeItem;
+              }
+            });
+
+            for (let i = 0; i < enableBackgroundDeclarations.length - 1; i++) {
+              newStyle.children.remove(enableBackgroundDeclarations[i]);
+            }
+          }
+        }
+
+        if (!hasFilter) {
+          delete node.attributes['enable-background'];
+
+          if (newStyle?.type === 'DeclarationList') {
+            if (enableBackgroundDeclaration) {
+              newStyle.children.remove(enableBackgroundDeclaration);
+            }
+
+            if (newStyle.children.isEmpty) {
+              delete node.attributes.style;
+            } else {
+              node.attributes.style = csstree.generate(newStyle);
+            }
+          }
+
+          return;
+        }
+
+        const hasDimensions =
+          node.attributes.width != null && node.attributes.height != null;
+
+        if (
+          (node.name === 'svg' ||
+            node.name === 'mask' ||
+            node.name === 'pattern') &&
+          hasDimensions
+        ) {
+          const attrValue = node.attributes['enable-background'];
+          const attrCleaned = cleanupValue(
+            attrValue,
+            node.name,
+            node.attributes.width,
+            node.attributes.height,
+          );
+
+          if (attrCleaned) {
+            node.attributes['enable-background'] = attrCleaned;
+          } else {
+            delete node.attributes['enable-background'];
+          }
+
+          if (
+            newStyle?.type === 'DeclarationList' &&
+            enableBackgroundDeclaration
+          ) {
+            const styleValue = csstree.generate(
+              // @ts-ignore
+              enableBackgroundDeclaration.data.value,
+            );
+            const styleCleaned = cleanupValue(
+              styleValue,
+              node.name,
+              node.attributes.width,
+              node.attributes.height,
+            );
+
+            if (styleCleaned) {
+              // @ts-ignore
+              enableBackgroundDeclaration.data.value = {
+                type: 'Raw',
+                value: styleCleaned,
+              };
+            } else {
+              newStyle.children.remove(enableBackgroundDeclaration);
+            }
+          }
+        }
+
+        if (newStyle?.type === 'DeclarationList') {
+          if (newStyle.children.isEmpty) {
+            delete node.attributes.style;
+          } else {
+            node.attributes.style = csstree.generate(newStyle);
+          }
+        }
+      },
+    },
+  };
+};
+
+/**
+ * @param {string} value Value of a enable-background attribute or style declaration.
+ * @param {string} nodeName Name of the node the value was assigned to.
+ * @param {string} width Width of the node the value was assigned to.
+ * @param {string} height Height of the node the value was assigned to.
+ * @returns {string | undefined} Cleaned up value, or undefined if it's redundant.
+ */
+const cleanupValue = (value, nodeName, width, height) => {
+  const match = regEnableBackground.exec(value);
+
+  if (match != null && width === match[1] && height === match[3]) {
+    return nodeName === 'svg' ? undefined : 'new';
+  }
+
+  return value;
+};