diff --git a/src/address-edit/index.js b/src/address-edit/index.js
index d0be37062..8151f7252 100644
--- a/src/address-edit/index.js
+++ b/src/address-edit/index.js
@@ -1,5 +1,5 @@
 // Utils
-import { createNamespace, isObj } from '../utils';
+import { createNamespace, isObject } from '../utils';
 import { isMobile } from '../utils/validate/mobile';
 
 // Components
@@ -95,7 +95,7 @@ export default createComponent({
 
   computed: {
     areaListLoaded() {
-      return isObj(this.areaList) && Object.keys(this.areaList).length;
+      return isObject(this.areaList) && Object.keys(this.areaList).length;
     },
 
     areaText() {
diff --git a/src/circle/index.js b/src/circle/index.js
index dbc17151e..2e70ef031 100644
--- a/src/circle/index.js
+++ b/src/circle/index.js
@@ -1,4 +1,4 @@
-import { createNamespace, isObj, addUnit } from '../utils';
+import { createNamespace, isObject, addUnit } from '../utils';
 import { raf, cancelRaf } from '../utils/dom/raf';
 import { BLUE, WHITE } from '../utils/constant';
 
@@ -101,7 +101,7 @@ export default createComponent({
     },
 
     gradient() {
-      return isObj(this.color);
+      return isObject(this.color);
     },
 
     LinearGradient() {
diff --git a/src/field/index.js b/src/field/index.js
index 57bcf1704..e45666d08 100644
--- a/src/field/index.js
+++ b/src/field/index.js
@@ -3,7 +3,7 @@ import { formatNumber } from './utils';
 import { isIOS } from '../utils/validate/system';
 import { preventDefault } from '../utils/dom/event';
 import { resetScroll } from '../utils/dom/reset-scroll';
-import { createNamespace, isObj, isDef, addUnit } from '../utils';
+import { createNamespace, isObject, isDef, addUnit } from '../utils';
 
 // Components
 import Icon from '../icon';
@@ -206,7 +206,7 @@ export default createComponent({
       input.style.height = 'auto';
 
       let height = input.scrollHeight;
-      if (isObj(this.autosize)) {
+      if (isObject(this.autosize)) {
         const { maxHeight, minHeight } = this.autosize;
         if (maxHeight) {
           height = Math.min(height, maxHeight);
diff --git a/src/notify/index.ts b/src/notify/index.ts
index dfd1d7491..8e33dc360 100644
--- a/src/notify/index.ts
+++ b/src/notify/index.ts
@@ -1,7 +1,7 @@
 import Vue from 'vue';
 import VanNotify from './Notify';
 import { WHITE } from '../utils/constant';
-import { isObj, isServer } from '../utils';
+import { isObject, isServer } from '../utils';
 import { mount } from '../utils/functional';
 import { NotifyOptions } from 'types/notify';
 
@@ -9,7 +9,7 @@ let timer: number | NodeJS.Timeout;
 let instance: any;
 
 function parseOptions(message: NotifyOptions): NotifyOptions {
-  return isObj(message) ? message : ({ message } as NotifyOptions);
+  return isObject(message) ? message : { message };
 }
 
 function Notify(options: NotifyOptions) {
diff --git a/src/picker/PickerColumn.js b/src/picker/PickerColumn.js
index 1e9c4af02..b2de06b74 100644
--- a/src/picker/PickerColumn.js
+++ b/src/picker/PickerColumn.js
@@ -1,5 +1,5 @@
 import { deepClone } from '../utils/deep-clone';
-import { createNamespace, isObj } from '../utils';
+import { createNamespace, isObject } from '../utils';
 import { range } from '../utils/format/number';
 import { preventDefault } from '../utils/dom/event';
 import { TouchMixin } from '../mixins/touch';
@@ -23,7 +23,7 @@ function getElementTranslateY(element) {
 }
 
 function isOptionDisabled(option) {
-  return isObj(option) && option.disabled;
+  return isObject(option) && option.disabled;
 }
 
 export default createComponent({
@@ -176,9 +176,10 @@ export default createComponent({
     },
 
     getOptionText(option) {
-      return isObj(option) && this.valueKey in option
-        ? option[this.valueKey]
-        : option;
+      if (isObject(option) && this.valueKey in option) {
+        return option[this.valueKey];
+      }
+      return option;
     },
 
     setIndex(index, userAction) {
diff --git a/src/tabbar-item/index.js b/src/tabbar-item/index.js
index f5bf826a2..cbafc9a25 100644
--- a/src/tabbar-item/index.js
+++ b/src/tabbar-item/index.js
@@ -1,5 +1,5 @@
 // Utils
-import { createNamespace, isObj, isDef } from '../utils';
+import { createNamespace, isObject, isDef } from '../utils';
 import { route, routeProps } from '../utils/router';
 
 // Mixins
@@ -32,7 +32,7 @@ export default createComponent({
     routeActive() {
       const { to, $route } = this;
       if (to && $route) {
-        const config = isObj(to) ? to : { path: to };
+        const config = isObject(to) ? to : { path: to };
         const pathMatched = config.path === $route.path;
         const nameMatched = isDef(config.name) && config.name === $route.name;
 
diff --git a/src/toast/index.js b/src/toast/index.js
index 420c6d0bd..87ff23f38 100644
--- a/src/toast/index.js
+++ b/src/toast/index.js
@@ -1,6 +1,6 @@
 import Vue from 'vue';
 import VueToast from './Toast';
-import { isObj, isServer } from '../utils';
+import { isObject, isServer } from '../utils';
 
 const defaultOptions = {
   icon: '',
@@ -35,7 +35,7 @@ let currentOptions = {
 };
 
 function parseOptions(message) {
-  if (isObj(message)) {
+  if (isObject(message)) {
     return message;
   }
 
diff --git a/src/utils/create/component.ts b/src/utils/create/component.ts
index 46f338a29..5754ca181 100644
--- a/src/utils/create/component.ts
+++ b/src/utils/create/component.ts
@@ -2,6 +2,7 @@
  * Create a basic component with common options
  */
 import '../../locale';
+import { isFunction } from '..';
 import { camelize } from '../format/string';
 import { SlotsMixin } from '../../mixins/slots';
 import Vue, {
@@ -68,7 +69,7 @@ export function createComponent(name: string) {
   return function<Props = DefaultProps, Events = {}, Slots = {}>(
     sfc: VantComponentOptions | FunctionComponent
   ): TsxComponent<Props, Events, Slots> {
-    if (typeof sfc === 'function') {
+    if (isFunction(sfc)) {
       sfc = transformFunctionComponent(sfc);
     }
 
diff --git a/src/utils/create/i18n.ts b/src/utils/create/i18n.ts
index a1bf18ddb..2045901a2 100644
--- a/src/utils/create/i18n.ts
+++ b/src/utils/create/i18n.ts
@@ -1,4 +1,4 @@
-import { get } from '..';
+import { get, isFunction } from '..';
 import { camelize } from '../format/string';
 import locale from '../../locale';
 
@@ -9,7 +9,7 @@ export function createI18N(name: string) {
     const messages = locale.messages();
     const message = get(messages, prefix + path) || get(messages, path);
 
-    return typeof message === 'function' ? message(...args) : message;
+    return isFunction(message) ? message(...args) : message;
   };
 }
 
diff --git a/src/utils/deep-assign.ts b/src/utils/deep-assign.ts
index 6ce75ac8d..0cb51d0d6 100644
--- a/src/utils/deep-assign.ts
+++ b/src/utils/deep-assign.ts
@@ -1,4 +1,4 @@
-import { isDef, isObj } from '.';
+import { isDef, isObject } from '.';
 import { ObjectIndex } from './types';
 
 const { hasOwnProperty } = Object.prototype;
@@ -10,11 +10,7 @@ function assignKey(to: ObjectIndex, from: ObjectIndex, key: string) {
     return;
   }
 
-  if (
-    !hasOwnProperty.call(to, key) ||
-    !isObj(val) ||
-    typeof val === 'function'
-  ) {
+  if (!hasOwnProperty.call(to, key) || !isObject(val)) {
     to[key] = val;
   } else {
     // eslint-disable-next-line no-use-before-define
diff --git a/src/utils/index.ts b/src/utils/index.ts
index 07f0a361b..c78525d6a 100644
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@@ -7,13 +7,16 @@ export const isServer: boolean = Vue.prototype.$isServer;
 
 export function noop() {}
 
-export function isDef(value: any): boolean {
-  return value !== undefined && value !== null;
+export function isDef(val: any): boolean {
+  return val !== undefined && val !== null;
 }
 
-export function isObj(x: any): boolean {
-  const type = typeof x;
-  return x !== null && (type === 'object' || type === 'function');
+export function isFunction(val: unknown): val is Function {
+  return typeof val === 'function';
+}
+
+export function isObject(val: any): val is Record<any, any> {
+  return val !== null && typeof val === 'object';
 }
 
 export function get(object: any, path: string): any {