flow like the river

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

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+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.default = minifyConditionalComments;
+
+var _htmlnano = _interopRequireDefault(require("../htmlnano"));
+
+var _helpers = require("../helpers");
+
+function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
+
+// Spec: https://docs.microsoft.com/en-us/previous-versions/windows/internet-explorer/ie-developer/compatibility/ms537512(v=vs.85)
+const CONDITIONAL_COMMENT_REGEXP = /(<!--\[if\s+?[^<>[\]]+?]>)([\s\S]+?)(<!\[endif\]-->)/gm;
+/** Minify content inside conditional comments */
+
+async function minifyConditionalComments(tree, htmlnanoOptions) {
+  // forEach, tree.walk, tree.match just don't support Promise.
+  for (let i = 0, len = tree.length; i < len; i++) {
+    const node = tree[i];
+
+    if (typeof node === 'string' && (0, _helpers.isConditionalComment)(node)) {
+      tree[i] = await minifycontentInsideConditionalComments(node, htmlnanoOptions);
+    }
+
+    if (node.content && node.content.length) {
+      tree[i].content = await minifyConditionalComments(node.content, htmlnanoOptions);
+    }
+  }
+
+  return tree;
+}
+
+async function minifycontentInsideConditionalComments(text, htmlnanoOptions) {
+  let match;
+  const matches = []; // FIXME!
+  // String#matchAll is supported since Node.js 12
+
+  while ((match = CONDITIONAL_COMMENT_REGEXP.exec(text)) !== null) {
+    matches.push([match[1], match[2], match[3]]);
+  }
+
+  if (!matches.length) {
+    return Promise.resolve(text);
+  }
+
+  return Promise.all(matches.map(async match => {
+    const result = await _htmlnano.default.process(match[1], htmlnanoOptions, {}, {});
+    let minified = result.html;
+
+    if (match[1].includes('<html') && minified.includes('</html>')) {
+      minified = minified.replace('</html>', '');
+    }
+
+    return match[0] + minified + match[2];
+  }));
+}