fix(js/ts) fix detecting types as JSX (#3278)

CHANGES.md

@@ -18,6 +18,8 @@ Parser:
 
 Grammars:
 
+- fix(ts) some complex types would classify as JSX (#3278) [Josh Goebel][]
+- fix(js/ts) less false positives for `class X extends Y` (#3278) [Josh Goebel][]
 - enh(css): add properties from several W3C (Candidate) Recommendations (#3308)
 - fix(js/ts) `Float32Array` highlighted incorrectly (#3353) [Josh Goebel][]
 - fix(css) single-colon psuedo-elements no longer break highlighting (#3240) [Josh Goebel][]

src/languages/javascript.js

@@ -28,6 +28,8 @@ export default function(hljs) {
     begin: '<>',
     end: '</>'
   };
+  // to avoid some special cases inside isTrulyOpeningTag
+  const XML_SELF_CLOSING = /<[A-Za-z0-9\\._:-]+\s*\/>/;
   const XML_TAG = {
     begin: /<[A-Za-z0-9\\._:-]+/,
     end: /\/[A-Za-z0-9\\._:-]+>|\/>/,
@@ -38,22 +40,43 @@ export default function(hljs) {
     isTrulyOpeningTag: (match, response) => {
       const afterMatchIndex = match[0].length + match.index;
       const nextChar = match.input[afterMatchIndex];
-      // nested type?
-      // HTML should not include another raw `<` inside a tag
-      // But a type might: `<Array<Array<number>>`, etc.
-      if (nextChar === "<") {
+      if (
+        // HTML should not include another raw `<` inside a tag
+        // nested type?
+        // `<Array<Array<number>>`, etc.
+        nextChar === "<" ||
+        // the , gives away that this is not HTML
+        // `<T, A extends keyof T, V>`
+        nextChar === ",") {
         response.ignoreMatch();
         return;
       }
-      // <something>
-      // This is now either a tag or a type.
+
+      // `<something>`
+      // Quite possibly a tag, lets look for a matching closing tag...
       if (nextChar === ">") {
         // if we cannot find a matching closing tag, then we
         // will ignore it
         if (!hasClosingTag(match, { after: afterMatchIndex })) {
           response.ignoreMatch();
         }
       }
+
+      // `<blah />` (self-closing)
+      // handled by simpleSelfClosing rule
+
+      // `<From extends string>`
+      // technically this could be HTML, but it smells like a type
+      let m;
+      const afterMatch = match.input.substr(afterMatchIndex);
+      // NOTE: This is ugh, but added specifically for https://github.com/highlightjs/highlight.js/issues/3276
+      if ((m = afterMatch.match(/^\s+extends\s+/))) {
+        if (m.index === 0) {
+          response.ignoreMatch();
+          // eslint-disable-next-line no-useless-return
+          return;
+        }
+      }
     }
   };
   const KEYWORDS = {
@@ -227,28 +250,37 @@ export default function(hljs) {
   // ES6 classes
   const CLASS_OR_EXTENDS = {
     variants: [
+      // class Car extends vehicle
       {
         match: [
           /class/,
           /\s+/,
-          IDENT_RE
+          IDENT_RE,
+          /\s+/,
+          /extends/,
+          /\s+/,
+          regex.concat(IDENT_RE, "(", regex.concat(/\./, IDENT_RE), ")*")
         ],
         scope: {
           1: "keyword",
-          3: "title.class"
+          3: "title.class",
+          5: "keyword",
+          7: "title.class.inherited"
         }
       },
+      // class Car
       {
         match: [
-          /extends/,
+          /class/,
           /\s+/,
-          regex.concat(IDENT_RE, "(", regex.concat(/\./, IDENT_RE), ")*")
+          IDENT_RE
         ],
         scope: {
           1: "keyword",
-          3: "title.class.inherited"
+          3: "title.class"
         }
-      }
+      },
+
     ]
   };
 
@@ -390,7 +422,7 @@ export default function(hljs) {
     aliases: ['js', 'jsx', 'mjs', 'cjs'],
     keywords: KEYWORDS,
     // this will be extended by TypeScript
-    exports: { PARAMS_CONTAINS },
+    exports: { PARAMS_CONTAINS, CLASS_REFERENCE },
     illegal: /#(?![$_A-z])/,
     contains: [
       hljs.SHEBANG({
@@ -464,6 +496,7 @@ export default function(hljs) {
           { // JSX
             variants: [
               { begin: FRAGMENT.begin, end: FRAGMENT.end },
+              { match: XML_SELF_CLOSING },
               {
                 begin: XML_TAG.begin,
                 // we carefully check the opening tag to see if it truly

src/languages/typescript.js

@@ -12,19 +12,9 @@ import javascript from "./javascript.js";
 
 /** @type LanguageFn */
 export default function(hljs) {
+  const tsLanguage = javascript(hljs);
+
   const IDENT_RE = ECMAScript.IDENT_RE;
-  const NAMESPACE = {
-    beginKeywords: 'namespace', end: /\{/, excludeEnd: true
-  };
-  const INTERFACE = {
-    beginKeywords: 'interface', end: /\{/, excludeEnd: true,
-    keywords: 'interface extends'
-  };
-  const USE_STRICT = {
-    className: 'meta',
-    relevance: 10,
-    begin: /^\s*['"]use strict['"]/
-  };
   const TYPES = [
     "any",
     "void",
@@ -35,6 +25,31 @@ export default function(hljs) {
     "never",
     "enum"
   ];
+  const NAMESPACE = {
+    beginKeywords: 'namespace',
+    end: /\{/,
+    excludeEnd: true,
+    contains: [
+      tsLanguage.exports.CLASS_REFERENCE
+    ]
+  };
+  const INTERFACE = {
+    beginKeywords: 'interface',
+    end: /\{/,
+    excludeEnd: true,
+    keywords: {
+      keyword: 'interface extends',
+      built_in: TYPES
+    },
+    contains: [
+      tsLanguage.exports.CLASS_REFERENCE
+    ]
+  };
+  const USE_STRICT = {
+    className: 'meta',
+    relevance: 10,
+    begin: /^\s*['"]use strict['"]/
+  };
   const TS_SPECIFIC_KEYWORDS = [
     "type",
     "namespace",
@@ -67,7 +82,6 @@ export default function(hljs) {
     mode.contains.splice(indx, 1, replacement);
   };
 
-  const tsLanguage = javascript(hljs);
 
   // this should update anywhere keywords is used since
   // it will be the same actual JS object

test/markup/javascript/jsx.expect.txt

@@ -25,3 +25,21 @@
 }
 
 <span class="hljs-keyword">var</span> x = <span class="hljs-number">5</span>;
+
+<span class="hljs-comment">// this is NOT JSX and should not trigger the rule</span>
+interface <span class="hljs-title class_">Prefixer</span>&lt;<span class="hljs-title class_">Something</span> <span class="hljs-keyword">extends</span> string&gt; {
+  (): <span class="hljs-string">`other__<span class="hljs-subst">${Something}</span>`</span>;
+
+  <span class="hljs-attr">parse</span>: &lt;<span class="hljs-title class_">From</span> <span class="hljs-keyword">extends</span> string&gt;<span class="hljs-function">(<span class="hljs-params">
+    value: From
+  </span>) =&gt;</span> number;
+}
+
+<span class="hljs-keyword">const</span> cloneWith = &lt;T, A <span class="hljs-keyword">extends</span> keyof T, V&gt;(
+  <span class="hljs-attr">i</span>: T,
+  <span class="hljs-attr">a</span>: A,
+  <span class="hljs-attr">value</span>: V
+): <span class="hljs-title class_">Omit</span>&lt;T, A&gt; &amp; {[K <span class="hljs-keyword">in</span> A]: V} =&gt; ({
+  ...i,
+  [a]: value,
+});

test/markup/javascript/jsx.txt

@@ -25,3 +25,21 @@ class App extends Component {
 }
 
 var x = 5;
+
+// this is NOT JSX and should not trigger the rule
+interface Prefixer<Something extends string> {
+  (): `other__${Something}`;
+
+  parse: <From extends string>(
+    value: From
+  ) => number;
+}
+
+const cloneWith = <T, A extends keyof T, V>(
+  i: T,
+  a: A,
+  value: V
+): Omit<T, A> & {[K in A]: V} => ({
+  ...i,
+  [a]: value,
+});