feat(html): support ie conditional start/end comment

src/language-html/conditional-comment.js

@@ -0,0 +1,80 @@
+"use strict";
+
+// https://css-tricks.com/how-to-create-an-ie-only-stylesheet
+
+// <!--[if ... ]> ... <![endif]-->
+const IE_CONDITIONAL_START_END_COMMENT_REGEX = /^(\[if([^\]]*?)\]>)([\s\S]*?)<!\s*\[endif\]$/;
+// <!--[if ... ]><!-->
+const IE_CONDITIONAL_START_COMMENT_REGEX = /^\[if([^\]]*?)\]><!$/;
+// <!--<![endif]-->
+const IE_CONDITIONAL_END_COMMENT_REGEX = /^<!\s*\[endif\]$/;
+
+const REGEX_PARSE_TUPLES = [
+  [IE_CONDITIONAL_START_END_COMMENT_REGEX, parseIeConditionalStartEndComment],
+  [IE_CONDITIONAL_START_COMMENT_REGEX, parseIeConditionalStartComment],
+  [IE_CONDITIONAL_END_COMMENT_REGEX, parseIeConditionalEndComment]
+];
+
+function parseIeConditionalComment(node, parseHtml) {
+  if (node.value) {
+    let match;
+    for (const [regex, parse] of REGEX_PARSE_TUPLES) {
+      if ((match = node.value.match(regex))) {
+        return parse(node, parseHtml, match);
+      }
+    }
+  }
+  return null;
+}
+
+function parseIeConditionalStartEndComment(node, parseHtml, match) {
+  const [, openingTagSuffix, condition, data] = match;
+  const offset = "<!--".length + openingTagSuffix.length;
+  const contentStartSpan = node.sourceSpan.start.moveBy(offset);
+  const contentEndSpan = contentStartSpan.moveBy(data.length);
+  const ParseSourceSpan = node.sourceSpan.constructor;
+  const [complete, children] = (() => {
+    try {
+      return [true, parseHtml(data, contentStartSpan).children];
+    } catch (e) {
+      const text = {
+        type: "text",
+        value: data,
+        sourceSpan: new ParseSourceSpan(contentStartSpan, contentEndSpan)
+      };
+      return [false, [text]];
+    }
+  })();
+  return {
+    type: "ieConditionalComment",
+    complete,
+    children,
+    condition: condition.trim().replace(/\s+/g, " "),
+    sourceSpan: node.sourceSpan,
+    startSourceSpan: new ParseSourceSpan(
+      node.sourceSpan.start,
+      contentStartSpan
+    ),
+    endSourceSpan: new ParseSourceSpan(contentEndSpan, node.sourceSpan.end)
+  };
+}
+
+function parseIeConditionalStartComment(node, parseHtml, match) {
+  const [, condition] = match;
+  return {
+    type: "ieConditionalStartComment",
+    condition: condition.trim().replace(/\s+/g, " "),
+    sourceSpan: node.sourceSpan
+  };
+}
+
+function parseIeConditionalEndComment(node /*, parseHtml, match */) {
+  return {
+    type: "ieConditionalEndComment",
+    sourceSpan: node.sourceSpan
+  };
+}
+
+module.exports = {
+  parseIeConditionalComment
+};

src/language-html/parser-html.js

@@ -5,6 +5,7 @@ const { HTML_ELEMENT_ATTRIBUTES, HTML_TAGS } = require("./utils");
 const { hasPragma } = require("./pragma");
 const createError = require("../common/parser-create-error");
 const { Node } = require("./ast");
+const { parseIeConditionalComment } = require("./conditional-comment");
 
 function ngHtmlParser(input, canSelfClose) {
   const parser = require("angular-html-parser");
@@ -240,50 +241,6 @@ function _parse(
   });
 }
 
-function parseIeConditionalComment(node, parseHtml) {
-  if (!node.value) {
-    return null;
-  }
-
-  const match = node.value.match(
-    /^(\[if([^\]]*?)\]>)([\s\S]*?)<!\s*\[endif\]$/
-  );
-
-  if (!match) {
-    return null;
-  }
-
-  const [, openingTagSuffix, condition, data] = match;
-  const offset = "<!--".length + openingTagSuffix.length;
-  const contentStartSpan = node.sourceSpan.start.moveBy(offset);
-  const contentEndSpan = contentStartSpan.moveBy(data.length);
-  const ParseSourceSpan = node.sourceSpan.constructor;
-  const [complete, children] = (() => {
-    try {
-      return [true, parseHtml(data, contentStartSpan).children];
-    } catch (e) {
-      const text = {
-        type: "text",
-        value: data,
-        sourceSpan: new ParseSourceSpan(contentStartSpan, contentEndSpan)
-      };
-      return [false, [text]];
-    }
-  })();
-  return {
-    type: "ieConditionalComment",
-    complete,
-    children,
-    condition: condition.trim().replace(/\s+/g, " "),
-    sourceSpan: node.sourceSpan,
-    startSourceSpan: new ParseSourceSpan(
-      node.sourceSpan.start,
-      contentStartSpan
-    ),
-    endSourceSpan: new ParseSourceSpan(contentEndSpan, node.sourceSpan.end)
-  };
-}
-
 function locStart(node) {
   return node.sourceSpan.start.offset;
 }

src/language-html/preprocess.js

@@ -12,6 +12,7 @@ const {
 
 const PREPROCESS_PIPELINE = [
   removeIgnorableFirstLf,
+  mergeIeConditonalStartEndCommentIntoElementOpeningTag,
   mergeCdataIntoText,
   extractInterpolation,
   extractWhitespaces,
@@ -52,6 +53,70 @@ function removeIgnorableFirstLf(ast /*, options */) {
   });
 }
 
+function mergeIeConditonalStartEndCommentIntoElementOpeningTag(
+  ast /*, options */
+) {
+  /**
+   *     <!--[if ...]><!--><target><!--<![endif]-->
+   */
+  const isTarget = node =>
+    node.type === "element" &&
+    node.prev &&
+    node.prev.type === "ieConditionalStartComment" &&
+    node.prev.sourceSpan.end.offset === node.startSourceSpan.start.offset &&
+    node.firstChild &&
+    node.firstChild.type === "ieConditionalEndComment" &&
+    node.firstChild.sourceSpan.start.offset === node.startSourceSpan.end.offset;
+  return ast.map(node => {
+    if (node.children) {
+      const isTargetResults = node.children.map(isTarget);
+      if (isTargetResults.some(Boolean)) {
+        const newChildren = [];
+
+        for (let i = 0; i < node.children.length; i++) {
+          const child = node.children[i];
+
+          if (isTargetResults[i + 1]) {
+            // ieConditionalStartComment
+            continue;
+          }
+
+          if (isTargetResults[i]) {
+            const ieConditionalStartComment = child.prev;
+            const ieConditionalEndComment = child.firstChild;
+
+            const ParseSourceSpan = child.sourceSpan.constructor;
+            const startSourceSpan = new ParseSourceSpan(
+              ieConditionalEndComment.sourceSpan.start,
+              ieConditionalEndComment.sourceSpan.end
+            );
+            const sourceSpan = new ParseSourceSpan(
+              startSourceSpan.start,
+              child.sourceSpan.end
+            );
+
+            newChildren.push(
+              child.clone({
+                condition: ieConditionalStartComment.condition,
+                sourceSpan,
+                startSourceSpan,
+                children: child.children.slice(1)
+              })
+            );
+
+            continue;
+          }
+
+          newChildren.push(child);
+        }
+
+        return node.clone({ children: newChildren });
+      }
+    }
+    return node;
+  });
+}
+
 function mergeNodeIntoText(ast, shouldMerge, getValue) {
   return ast.map(node => {
     if (node.children) {

src/language-html/printer-html.js

@@ -255,6 +255,9 @@ function genericPrint(path, options, print) {
         printClosingTag(node)
       ]);
     }
+    case "ieConditionalStartComment":
+    case "ieConditionalEndComment":
+      return concat([printOpeningTagStart(node), printClosingTagEnd(node)]);
     case "interpolation":
       return concat([
         printOpeningTagStart(node),
@@ -770,11 +773,19 @@ function printOpeningTagStartMarker(node) {
     case "comment":
       return "<!--";
     case "ieConditionalComment":
+    case "ieConditionalStartComment":
       return `<!--[if ${node.condition}`;
+    case "ieConditionalEndComment":
+      return `<!--<!`;
     case "interpolation":
       return "{{";
     case "docType":
       return "<!DOCTYPE";
+    case "element":
+      if (node.condition) {
+        return `<!--[if ${node.condition}]><!--><${node.rawName}`;
+      }
+    // fall through
     default:
       return `<${node.rawName}`;
   }
@@ -785,6 +796,11 @@ function printOpeningTagEndMarker(node) {
   switch (node.type) {
     case "ieConditionalComment":
       return "]>";
+    case "element":
+      if (node.condition) {
+        return `><!--<![endif]-->`;
+      }
+    // fall through
     default:
       return `>`;
   }
@@ -811,7 +827,10 @@ function printClosingTagEndMarker(node) {
     case "comment":
       return "-->";
     case "ieConditionalComment":
+    case "ieConditionalEndComment":
       return `[endif]-->`;
+    case "ieConditionalStartComment":
+      return `]><!-->`;
     case "interpolation":
       return "}}";
     case "element":