Add jsdoc rules to linter and fix errors (#12)

Author: Beatriz Rizental

.eslintrc

@@ -17,8 +17,14 @@
       }
     ],
     "semi": ["error", "always"],
-    "no-debugger":  ["error"]
+    "no-debugger":  ["error"],
+    "jsdoc/no-types": "off",
+    "jsdoc/require-param-type": "off",
+    "jsdoc/require-returns-type": "off"
   },
+  "extends": [
+    "plugin:jsdoc/recommended"
+  ],
   "parser": "@typescript-eslint/parser",
   "plugins": [
     "@typescript-eslint",

src/storage/persistent/webext.ts

@@ -44,7 +44,7 @@ class WebExtStore implements Store {
    *
    * @param index The index to the given entry on the storage.
    *
-   * @return The query object.
+   * @returns The query object.
    */
   private _buildQuery(index: StorageIndex): WebExtStoreQuery {
     let partialQuery = null;

src/utils.ts

@@ -2,14 +2,38 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 
+/**
+ * Checks whether or not `v` is a simple data object.
+ *
+ * @param v The value to verify.
+ *
+ * @returns A special Typescript value (which compiles down to a boolean)
+ *          stating wether `v` is a valid data object.
+ */
 export function isObject(v: unknown): v is Record<string | number | symbol, unknown> {
   return (v && typeof v === "object" && v.constructor === Object);
 }
 
+/**
+ * Checks whether or not `v` is undefined.
+ *
+ * @param v The value to verify.
+ *
+ * @returns A special Typescript value (which compiles down to a boolean)
+ *          stating wether `v` is undefined.
+ */
 export function isUndefined(v: unknown): v is undefined {
   return typeof v === "undefined";
 }
 
+/**
+ * Checks whether or not `v` is a string.
+ *
+ * @param v The value to verify.
+ *
+ * @returns A special Typescript value (which compiles down to a boolean)
+ *          stating wether `v` is a string.
+ */
 export function isString(v: unknown): v is string {
   return (v && (typeof v === "string" || (v === "object" && v.constructor === String)));
 }

tests/utils/webext/index.ts

@@ -65,6 +65,8 @@ export async function setupFirefox(headless: boolean): Promise<WebDriver> {
  * @param browser A Webdriver where we will run this proxied script
  * @param method The method which we want to execute.
  *        This array will work exactly like the StorageIndex.
+ *
+ * @returns A proxy function for the given browser method.
  */
 export function webExtensionAPIProxyBuilder(browser: WebDriver, method: string[]) {
   return async function (...args: never[]): Promise<any> {