fix: no language provided and undefined highlight-lines (#43)

* fix: no language provided and undefined highlight-lines

* docs: fix highlight-lines undefined

Author: peterpeterparker

CHANGELOG.md

@@ -1,3 +1,9 @@
+# 3.0.1 (2021-07-28)
+
+### Fix
+
+- no language provided results in an `undefined` value for the attribute highlight-lines ([#40](https://github.com/deckgo/gatsby-remark-highlight-code/issues/40))
+
 # 3.0.0 (2021-05-22)
 
 ### Breaking Changes

README.md

@@ -193,7 +193,7 @@ Single or multiple lines of code can be highlighted.
   <img src="https://raw.githubusercontent.com/deckgo/gatsby-remark-highlight-code/master/static/highlight-lines.gif" alt="Highlight lines" width="50%">
 </div>
 
-The Markdown syntax is the following: next to the specification of the language, between brackets `{}`, the lines should be provided in a comma separated list. A single line can be provided (for example `dart{1}`) or multiple one, from and to being separated with a dash (for example `javascript{3-6}`). Both single or multiple lines can be mixed (for example `typescript{2, 3,4, 7, 8-15}`).
+The Markdown syntax is the following: next to the specification of the language, between brackets `{}`, the lines should be provided in a comma separated list. A single line can be provided (for example `dart{1}`) or multiple one, from and to being separated with a dash (for example `javascript{3-6}`). Both single or multiple lines can be mixed (for example `typescript{2, 3-4, 7, 8-15}`).
 
 Animation between the selected highlighted groups can be triggered with the help of methods (see component [@deckdeckgo/highlight-code] documentation for details).  
 

utils.js

@@ -69,15 +69,16 @@ function generatePropsString(pluginOptions) {
 
 function parseNodeHtml(node, pluginOptions) {
   let lang = "",
-      highlightLines;
+      highlightLines = undefined;
+
   if (node && node.lang !== null) {
     ({ lang, highlightLines } = parseLanguageAndHighlightedLines(node));
   }
   const text = toString(node);
   const properties = generatePropsString(pluginOptions);
 
-  const renderLang = lang !== '' ? `language="${lang}"` : '';
-  const renderHighlightLines = highlightLines !== '' ? `highlight-lines="${highlightLines}"` : '';
+  const renderLang = lang !== '' && lang !== undefined ? `language="${lang}"` : '';
+  const renderHighlightLines = highlightLines !== '' && highlightLines !== undefined ? `highlight-lines="${highlightLines}"` : '';
 
   return `<deckgo-highlight-code ${renderLang} ${properties} ${renderHighlightLines}>
           <code slot="code">${_.escape(text)}</code>

utils.test.js

@@ -62,35 +62,49 @@ describe("parse node to html", () => {
           <code slot="code">hello world</code>
         </deckgo-highlight-code>`);
   });
+
+    it("should parse no language and no highlight lines for null language", () => {
+        const html = parseNodeHtml(
+            {
+                value: "hello world",
+                lang: null,
+            },
+            {}
+        );
+
+        expect(html).toEqual(`<deckgo-highlight-code   >
+          <code slot="code">hello world</code>
+        </deckgo-highlight-code>`);
+    });
 });
 
 describe("languages extraction", () => {
-  test("detects the languages correctly", () => {
-    expect(parseLanguageAndHighlightedLines(dartLangNode).lang).toBe("dart");
-    expect(parseLanguageAndHighlightedLines(dartLangWithSpacesNode).lang).toBe(
-      "dart"
-    );
-    expect(parseLanguageAndHighlightedLines(typescriptLangNode).lang).toBe(
-      "typescript"
-    );
-    expect(
-      parseLanguageAndHighlightedLines(typescriptWithLinesGroupNode).lang
-    ).toBe("typescript");
-  });
+    test("detects the languages correctly", () => {
+        expect(parseLanguageAndHighlightedLines(dartLangNode).lang).toBe("dart");
+        expect(parseLanguageAndHighlightedLines(dartLangWithSpacesNode).lang).toBe(
+            "dart"
+        );
+        expect(parseLanguageAndHighlightedLines(typescriptLangNode).lang).toBe(
+            "typescript"
+        );
+        expect(
+            parseLanguageAndHighlightedLines(typescriptWithLinesGroupNode).lang
+        ).toBe("typescript");
+    });
 
-  test("detects the highlight-lines correctly", () => {
-    expect(parseLanguageAndHighlightedLines(dartLangNode).highlightLines).toBe(
-      "3 4 5"
-    );
-    expect(
-      parseLanguageAndHighlightedLines(dartLangWithSpacesNode).highlightLines
-    ).toBe("5 9 34 39,44");
-    expect(
-      parseLanguageAndHighlightedLines(typescriptLangNode).highlightLines
-    ).toBe("");
-    expect(
-      parseLanguageAndHighlightedLines(typescriptWithLinesGroupNode)
-        .highlightLines
-    ).toBe("3 4 5,9 22,45");
-  });
+    test("detects the highlight-lines correctly", () => {
+        expect(parseLanguageAndHighlightedLines(dartLangNode).highlightLines).toBe(
+            "3 4 5"
+        );
+        expect(
+            parseLanguageAndHighlightedLines(dartLangWithSpacesNode).highlightLines
+        ).toBe("5 9 34 39,44");
+        expect(
+            parseLanguageAndHighlightedLines(typescriptLangNode).highlightLines
+        ).toBe("");
+        expect(
+            parseLanguageAndHighlightedLines(typescriptWithLinesGroupNode)
+                .highlightLines
+        ).toBe("3 4 5,9 22,45");
+    });
 });