1 files changed, 74 insertions, 0 deletions
diff --git a/app.js b/app.js
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index 0000000..1080a20
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+const visit = require('unist-util-visit');
+
+
+const PLUGIN_NAME = 'remark-mermaid-simple';
+
+/**
+ * Given the MDAST ast, look for all fenced codeblocks that have a language of
+ * `mermaid` and pass that to mermaid.cli to render the image. Replaces the
+ * codeblocks with an image of the rendered graph.
+ *
+ * @param {object} ast
+ * @param {vFile} vFile
+ * @return {function}
+ */
+function visitCodeBlock(ast, vFile) {
+  return visit(ast, 'code', (node, index, parent) => {
+    const { lang, value, position } = node;
+    const destinationDir = getDestinationDir(vFile);
+
+    // If this codeblock is not mermaid, bail.
+    if (lang !== 'mermaid') {
+      return node;
+    }
+
+    const image = {
+      type: 'mermaid',
+      value: value,
+      data: {
+        hName: 'div',
+        hProperties: {
+          className: 'mermaid'
+        },
+        hChildren: [
+          {
+            type: 'text',
+            value: value
+          }
+        ]
+      }
+    };
+
+    parent.children.splice(index, 1, image);
+
+    return node;
+  });
+}
+
+/**
+ * Returns the transformer which acst on the MDAST tree and given VFile.
+ *
+ * @link https://github.com/unifiedjs/unified#function-transformernode-file-next
+ * @link https://github.com/syntax-tree/mdast
+ * @link https://github.com/vfile/vfile
+ * @return {function}
+ */
+function mermaid() {
+  /**
+   * @param {object} ast MDAST
+   * @param {vFile} vFile
+   * @param {function} next
+   * @return {object}
+   */
+  return function transformer(ast, vFile, next) {
+    visitCodeBlock(ast, vFile);
+
+    if (typeof next === 'function') {
+      return next(null, ast, vFile);
+    }
+
+    return ast;
+  };
+}
+
+module.exports = mermaid;