initial commit

lib/remark-extract-frontmatter.ts

@@ -0,0 +1,13 @@
+import { Parent } from 'unist'
+import { VFile } from 'vfile'
+import { visit } from 'unist-util-visit'
+import { load } from 'js-yaml'
+
+export default function extractFrontmatter() {
+  return (tree: Parent, file: VFile) => {
+    visit(tree, 'yaml', (node: Parent) => {
+      //@ts-ignore
+      file.data.frontmatter = load(node.value)
+    })
+  }
+}