flow like the river

BACK_BACK/node_modules/htmlnano/lib/modules/removeUnusedCss.js

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+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = removeUnusedCss;
+
+var _helpers = require("../helpers");
+
+var _uncss = _interopRequireDefault(require("uncss"));
+
+var _purgecss = _interopRequireDefault(require("purgecss"));
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+// These options must be set and shouldn't be overriden to ensure uncss doesn't look at linked stylesheets.
+const uncssOptions = {
+  ignoreSheets: [/\s*/],
+  stylesheets: []
+};
+
+function processStyleNodeUnCSS(html, styleNode, uncssOptions) {
+  const css = (0, _helpers.extractCssFromStyleNode)(styleNode);
+  return runUncss(html, css, uncssOptions).then(css => {
+    // uncss may have left some style tags empty
+    if (css.trim().length === 0) {
+      styleNode.tag = false;
+      styleNode.content = [];
+      return;
+    }
+
+    styleNode.content = [css];
+  });
+}
+
+function runUncss(html, css, userOptions) {
+  if (typeof userOptions !== 'object') {
+    userOptions = {};
+  }
+
+  const options = { ...userOptions,
+    ...uncssOptions
+  };
+  return new Promise((resolve, reject) => {
+    options.raw = css;
+    (0, _uncss.default)(html, options, (error, output) => {
+      if (error) {
+        reject(error);
+        return;
+      }
+
+      resolve(output);
+    });
+  });
+}
+
+const purgeFromHtml = function (tree) {
+  // content is not used as we can directly used the parsed HTML,
+  // making the process faster
+  const selectors = [];
+  tree.walk(node => {
+    const classes = node.attrs && node.attrs.class && node.attrs.class.split(' ') || [];
+    const ids = node.attrs && node.attrs.id && node.attrs.id.split(' ') || [];
+    selectors.push(...classes, ...ids);
+    node.tag && selectors.push(node.tag);
+    return node;
+  });
+  return () => selectors;
+};
+
+function processStyleNodePurgeCSS(tree, styleNode, purgecssOptions) {
+  const css = (0, _helpers.extractCssFromStyleNode)(styleNode);
+  return runPurgecss(tree, css, purgecssOptions).then(css => {
+    if (css.trim().length === 0) {
+      styleNode.tag = false;
+      styleNode.content = [];
+      return;
+    }
+
+    styleNode.content = [css];
+  });
+}
+
+function runPurgecss(tree, css, userOptions) {
+  if (typeof userOptions !== 'object') {
+    userOptions = {};
+  }
+
+  const options = { ...userOptions,
+    content: [{
+      raw: tree,
+      extension: 'html'
+    }],
+    css: [{
+      raw: css,
+      extension: 'css'
+    }],
+    extractors: [{
+      extractor: purgeFromHtml(tree),
+      extensions: ['html']
+    }]
+  };
+  return new _purgecss.default().purge(options).then(result => {
+    return result[0].css;
+  });
+}
+/** Remove unused CSS */
+
+
+function removeUnusedCss(tree, options, userOptions) {
+  const promises = [];
+  const html = userOptions.tool !== 'purgeCSS' && tree.render(tree);
+  tree.walk(node => {
+    if ((0, _helpers.isStyleNode)(node)) {
+      if (userOptions.tool === 'purgeCSS') {
+        promises.push(processStyleNodePurgeCSS(tree, node, userOptions));
+      } else {
+        promises.push(processStyleNodeUnCSS(html, node, userOptions));
+      }
+    }
+
+    return node;
+  });
+  return Promise.all(promises).then(() => tree);
+}