export folder as md or text

browser/main/lib/dataApi/exportFolder.js

@@ -0,0 +1,64 @@
+const { findStorage } = require('browser/lib/findStorage')
+const resolveStorageData = require('./resolveStorageData')
+const resolveStorageNotes = require('./resolveStorageNotes')
+const path = require('path')
+const fs = require('fs')
+
+/**
+ * @param {String} storageKey
+ * @param {String} folderKey
+ * @param {String} fileType
+ * @param {String} exportDir
+ *
+ * @return {Object}
+ * ```
+ * {
+ *   storage: Object,
+ *   folderKey: String,
+ *   fileType: String,
+ *   exportDir: String
+ * }
+ * ```
+ */
+
+function exportFolder (storageKey, folderKey, fileType, exportDir) {
+  let targetStorage
+  try {
+    targetStorage = findStorage(storageKey)
+  } catch (e) {
+    return Promise.reject(e)
+  }
+
+  return resolveStorageData(targetStorage)
+    .then(function assignNotes (storage) {
+      return resolveStorageNotes(storage)
+        .then((notes) => {
+          return {
+            storage,
+            notes
+          }
+        })
+    })
+    .then(function exportNotes (data) {
+      const { storage, notes } = data
+
+      notes
+        .filter(note => note.folder === folderKey && note.isTrashed === false && note.type === 'MARKDOWN_NOTE')
+        .forEach(snippet => {
+          const notePath = path.join(exportDir, `${snippet.title}.${fileType}`)
+          console.log(notePath)
+          fs.writeFile(notePath, snippet.content, (err) => {
+            if (err) throw err
+          })
+        })
+
+      return {
+        storage,
+        folderKey,
+        fileType,
+        exportDir
+      }
+    })
+}
+
+module.exports = exportFolder