diff --git a/lib/create-promise.js b/lib/create-promise.js
index c32eb87..4b10c0b 100644
--- a/lib/create-promise.js
+++ b/lib/create-promise.js
@@ -1,10 +1,22 @@
 'use strict'
 
+/**
+ * @callback PromiseResolve
+ * @param {any|PromiseLike<any>} value
+ * @returns {void}
+ */
+
+/**
+ * @callback PromiseReject
+ * @param {any} reason
+ * @returns {void}
+ */
+
 /**
  * @typedef PromiseObject
  * @property {Promise} promise
- * @property {PromiseConstructor["resolve"]} resolve
- * @property {PromiseConstructor["reject"]} reject
+ * @property {PromiseResolve} resolve
+ * @property {PromiseReject} reject
  */
 
 /**
@@ -12,8 +24,8 @@
  */
 function createPromise () {
   /**
-     * @type {PromiseObject}
-     */
+   * @type {PromiseObject}
+   */
   const obj = {
     resolve: null,
     reject: null,
diff --git a/lib/is-bundled-or-typescript-plugin.js b/lib/is-bundled-or-typescript-plugin.js
index f72438e..42003dd 100644
--- a/lib/is-bundled-or-typescript-plugin.js
+++ b/lib/is-bundled-or-typescript-plugin.js
@@ -7,12 +7,15 @@
  */
 
 /**
- * @param {unknown} plugin
+ * @param {any} maybeBundledOrTypescriptPlugin
  * @returns {plugin is BundledOrTypescriptPlugin}
  */
-
-function isBundledOrTypescriptPlugin (plugin) {
-  return plugin !== null && typeof plugin === 'object' && typeof plugin.default === 'function'
+function isBundledOrTypescriptPlugin (maybeBundledOrTypescriptPlugin) {
+  return (
+    maybeBundledOrTypescriptPlugin !== null &&
+    typeof maybeBundledOrTypescriptPlugin === 'object' &&
+    typeof maybeBundledOrTypescriptPlugin.default === 'function'
+  )
 }
 
 module.exports = {
diff --git a/lib/validate-plugin.js b/lib/validate-plugin.js
index 4006ca4..374ee56 100644
--- a/lib/validate-plugin.js
+++ b/lib/validate-plugin.js
@@ -3,19 +3,20 @@
 const { AVV_ERR_PLUGIN_NOT_VALID } = require('./errors')
 
 /**
- * @param {unknown} plugin
+ * @param {any} maybePlugin
  * @throws {AVV_ERR_PLUGIN_NOT_VALID}
- * @returns {Function}
+ *
+ * @returns {asserts plugin is Function|PromiseLike}
  */
-function validatePlugin (plugin) {
+function validatePlugin (maybePlugin) {
   // validate if plugin is a function or Promise
-  if (!(plugin && (typeof plugin === 'function' || typeof plugin.then === 'function'))) {
-    if (Array.isArray(plugin)) {
+  if (!(maybePlugin && (typeof maybePlugin === 'function' || typeof maybePlugin.then === 'function'))) {
+    if (Array.isArray(maybePlugin)) {
       throw new AVV_ERR_PLUGIN_NOT_VALID('array')
-    } else if (plugin === null) {
+    } else if (maybePlugin === null) {
       throw new AVV_ERR_PLUGIN_NOT_VALID('null')
     } else {
-      throw new AVV_ERR_PLUGIN_NOT_VALID(typeof plugin)
+      throw new AVV_ERR_PLUGIN_NOT_VALID(typeof maybePlugin)
     }
   }
 }