Fixes #3

_src/eleventy-liquidjs-tag-highlight-plain.js

@@ -0,0 +1,32 @@
+module.exports = function(liquidEngine) {
+
+  return {
+    parse: function(tagToken, remainTokens) {
+      this.language = tagToken.args;
+      this.tokens = [];
+
+      var stream = liquidEngine.parser.parseStream(remainTokens);
+
+      stream
+        .on('token', token => {
+          if (token.name === 'endhighlight') {
+            stream.stop();
+          } else {
+            this.tokens.push(token); 
+          }
+        })
+        .on('end', x => {
+          throw new Error("tag highlight not closed");
+        });
+
+      stream.start();
+    },
+    render: function(scope, hash) {
+      var tokens = this.tokens.map(token => {
+        return token.raw.trim();
+      }).join('').trim();
+
+      return Promise.resolve(`<pre class="language-${this.language}"><code class="language-${this.language}">\n` + tokens + "\n</code></pre>");
+    }
+  }
+};

_src/eleventy-liquidjs-tag-highlight-prismjs.js

@@ -0,0 +1,37 @@
+const Prism = require('prismjs');
+
+module.exports = function(liquidEngine) {
+  let langMap = {
+    "css": "css",
+    "html": "markup",
+    "js": "javascript"
+  };
+
+  return {
+    parse: function(tagToken, remainTokens) {
+      this.language = langMap[ tagToken.args ] || tagToken.args;
+      this.tokens = [];
+
+      var stream = liquidEngine.parser.parseStream(remainTokens);
+
+      stream
+        .on('token', token => {
+          if (token.name === 'endhighlight') {
+            stream.stop();
+          } else {
+            this.tokens.push(token); 
+          }
+        })
+        .on('end', x => {
+          throw new Error("tag highlight not closed");
+        });
+
+      stream.start()
+    },
+    render: function(scope, hash) {
+      var tokens = this.tokens.map(token => token.raw).join('').trim();
+      var html = Prism.highlight(tokens, Prism.languages[ this.language ]);
+      return Promise.resolve(`<pre class="language-${this.language}"><code class="language-${this.language}">` + html + "</code></pre>");
+    }
+  }
+};