Add a few missing docblocks to background files

1 files changed, 31 insertions, 4 deletions

diff --git a/app/scripts/lib/migrator/index.js b/app/scripts/lib/migrator/index.js
index 85c2717ea..345ca8001 100644
--- a/app/scripts/lib/migrator/index.js
+++ b/app/scripts/lib/migrator/index.js
@@ -1,7 +1,23 @@
 const EventEmitter = require('events')
 
+/**
+ * @typedef {object} Migration
+ * @property {number} version - The migration version
+ * @property {Function} migrate - Returns a promise of the migrated data
+ */
+
+/**
+ * @typedef {object} MigratorOptions
+ * @property {Array<Migration>} [migrations] - The list of migrations to apply
+ * @property {number} [defaultVersion] - The version to use in the initial state
+ */
+
 class Migrator extends EventEmitter {
 
+  /**
+   * @constructor
+   * @param {MigratorOptions} opts
+   */
   constructor (opts = {}) {
     super()
     const migrations = opts.migrations || []
@@ -42,19 +58,30 @@ class Migrator extends EventEmitter {
 
     return versionedData
 
-    // migration is "pending" if it has a higher
-    // version number than currentVersion
+    /**
+     * Returns whether or not the migration is pending
+     *
+     * A migration is considered "pending" if it has a higher
+     * version number than the current version.
+     * @param {Migration} migration
+     * @returns {boolean}
+     */
     function migrationIsPending (migration) {
       return migration.version > versionedData.meta.version
     }
   }
 
-  generateInitialState (initState) {
+  /**
+   * Returns the initial state for the migrator
+   * @param {object} [data] - The data for the initial state
+   * @returns {{meta: {version: number}, data: any}}
+   */
+  generateInitialState (data) {
     return {
       meta: {
         version: this.defaultVersion,
       },
-      data: initState,
+      data,
     }
   }