add YAML front matter when exporting

browser/main/lib/dataApi/formatMarkdown.js

@@ -0,0 +1,94 @@
+import attachmentManagement from './attachmentManagement'
+import yaml from 'js-yaml'
+import path from 'path'
+
+const delimiterRegExp = /^\-{3}/
+
+/**
+ * ```
+ * {
+ *   storagePath,
+ *   export
+ * }
+ * ```
+ */
+export default function formatMarkdown (props) {
+  return function (note, targetPath, exportTasks) {
+    let result = note.content
+
+    if (props.storagePath && note.key) {
+      const attachmentsAbsolutePaths = attachmentManagement.getAbsolutePathsOfAttachmentsInContent(result, props.storagePath)
+
+      const destinationFolder = props.export.prefixAttachmentFolder ? `${path.parse(targetPath).name} - ${attachmentManagement.DESTINATION_FOLDER}` : attachmentManagement.DESTINATION_FOLDER
+
+      attachmentsAbsolutePaths.forEach(attachment => {
+        exportTasks.push({
+          src: attachment,
+          dst: destinationFolder
+        })
+      })
+
+      result = attachmentManagement.replaceStorageReferences(result, note.key, destinationFolder)
+    }
+
+    if (props.export.metadata === 'MERGE_HEADER') {
+      const metadata = getFrontMatter(result)
+
+      const values = Object.assign({}, note)
+      delete values.content
+      delete values.isTrashed
+
+      for (const key in values) {
+        metadata[key] = values[key]
+      }
+
+      result = replaceFrontMatter(result, metadata)
+    } else if (props.export.metadata === 'MERGE_VARIABLE') {
+      const metadata = getFrontMatter(result)
+
+      const values = Object.assign({}, note)
+      delete values.content
+      delete values.isTrashed
+
+      if (props.export.variable) {
+        metadata[props.export.variable] = values
+      } else {
+        for (const key in values) {
+          metadata[key] = values[key]
+        }
+      }
+
+      result = replaceFrontMatter(result, metadata)
+    }
+
+    return result
+  }
+}
+
+function getFrontMatter (markdown) {
+  const lines = markdown.split('\n')
+
+  if (delimiterRegExp.test(lines[0])) {
+    let line = 0
+    while (++line < lines.length && delimiterRegExp.test(lines[line])) {
+    }
+
+    return yaml.load(lines.slice(1, line).join('\n')) || {}
+  } else {
+    return {}
+  }
+}
+
+function replaceFrontMatter (markdown, metadata) {
+  const lines = markdown.split('\n')
+
+  if (lines[0] === '---') {
+    let line = 0
+    while (++line < lines.length && lines[line] !== '---') {
+    }
+
+    return `---\n${yaml.dump(metadata)}---\n${lines.slice(line + 1).join('\n')}`
+  } else {
+    return `---\n${yaml.dump(metadata)}---\n\n${markdown}`
+  }
+}