From ac238d1d58164071eafeb893992662e4e00c6aec Mon Sep 17 00:00:00 2001
From: Kelly Joseph Price <kellyjosephprice@gmail.com>
Date: Mon, 23 May 2022 15:11:13 -0700
Subject: [PATCH] feat: add yaml compiler (#509)
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## 🧰 Changes

Adds a compiler for frontmatter.

If you try to save a doc in the editor with frontmatter, the save currently fails! Something like the following:

```
---
title: Getting started
---

Coming content
```
---
 __tests__/flavored-compilers/yaml.test.js | 22 ++++++++++++++++++++++
 processor/compile/index.js                |  1 +
 processor/compile/yaml.js                 |  8 ++++++++
 3 files changed, 31 insertions(+)
 create mode 100644 __tests__/flavored-compilers/yaml.test.js
 create mode 100644 processor/compile/yaml.js

diff --git a/__tests__/flavored-compilers/yaml.test.js b/__tests__/flavored-compilers/yaml.test.js
new file mode 100644
index 000000000..877f1f03b
--- /dev/null
+++ b/__tests__/flavored-compilers/yaml.test.js
@@ -0,0 +1,22 @@
+import { mdast, md } from '../../index';
+
+describe('yaml compiler', () => {
+  it('correctly writes out yaml', () => {
+    const txt = `
+---
+title: This is test
+author: A frontmatter test
+---
+
+Document content!
+    `;
+
+    expect(md(mdast(txt))).toBe(`---
+title: This is test
+author: A frontmatter test
+---
+
+Document content!
+`);
+  });
+});
diff --git a/processor/compile/index.js b/processor/compile/index.js
index 1ae2e9f50..8910c1a76 100644
--- a/processor/compile/index.js
+++ b/processor/compile/index.js
@@ -13,3 +13,4 @@ export { default as rdmePinCompiler } from './pin';
 export { default as rdmeVarCompiler } from './var';
 export { default as tableCompiler } from './table';
 export { default as tableHeadCompiler } from './table-head';
+export { default as yamlCompiler } from './yaml';
diff --git a/processor/compile/yaml.js b/processor/compile/yaml.js
new file mode 100644
index 000000000..e493b80ca
--- /dev/null
+++ b/processor/compile/yaml.js
@@ -0,0 +1,8 @@
+module.exports = function YamlCompiler() {
+  const { Compiler } = this;
+  const { visitors } = Compiler.prototype;
+
+  visitors.yaml = function compile(node) {
+    return `---\n${node.value}\n---`;
+  };
+};