feat: Parse front matter as metadata

1 files changed, 46 insertions, 0 deletions

diff --git a/src/modules/metadata.js b/src/modules/metadata.js
new file mode 100644
index 0000000..9f24d8e
--- /dev/null
+++ b/src/modules/metadata.js
@@ -0,0 +1,46 @@
+'use strict'
+
+const fs = require('fs')
+const path = require('path')
+const matter = require('gray-matter')
+
+const options = {
+  lang: 'toml',
+  delims: '+++'
+}
+
+function* lowercaseKeys (iterator) {
+  for (let [k, v] of iterator) {
+    yield [String(k).toLowerCase(), v]
+  }
+}
+
+function canonicaliseMetadata (meta) {
+  if (meta.data) {
+    meta.data = new Map(lowercaseKeys(Object.entries(meta.data)))
+  } else {
+    meta.data = new Map()
+  }
+  return meta
+}
+
+function readFileMetadata (filename) {
+  return canonicaliseMetadata(matter.read(filename, options))
+}
+
+function getFileMetadata (filename) {
+  const result = readFileMetadata(filename)
+  return result && result.data
+}
+
+function getFolderMetadata (folder) {
+  return fs
+    .readdirSync(folder)
+    .map(f => path.resolve(folder, f))
+    .map(readFileMetadata)
+}
+
+module.exports = {
+  getFileMetadata,
+  getFolderMetadata
+}