diff --git a/packages/vant-touch-emulator/index.js b/packages/vant-touch-emulator/index.js
index dfa3607b7..25d873cb3 100644
--- a/packages/vant-touch-emulator/index.js
+++ b/packages/vant-touch-emulator/index.js
@@ -4,194 +4,199 @@
  * Source：https://github.com/hammerjs/touchemulator
  */
 
-var eventTarget;
-var supportTouch = 'ontouchstart' in window;
+(function () {
+  if (typeof window === 'undefined') {
+    return;
+  }
+  var eventTarget;
+  var supportTouch = 'ontouchstart' in window;
 
-// polyfills
-if (!document.createTouch) {
-  document.createTouch = function(
-    view,
-    target,
-    identifier,
-    pageX,
-    pageY,
-    screenX,
-    screenY
-  ) {
-    // auto set
-    return new Touch(
+  // polyfills
+  if (!document.createTouch) {
+    document.createTouch = function (
+      view,
       target,
       identifier,
-      {
-        pageX: pageX,
-        pageY: pageY,
-        screenX: screenX,
-        screenY: screenY,
-        clientX: pageX - window.pageXOffset,
-        clientY: pageY - window.pageYOffset,
-      },
-      0,
-      0
-    );
-  };
-}
-
-if (!document.createTouchList) {
-  document.createTouchList = function() {
-    var touchList = TouchList();
-    for (var i = 0; i < arguments.length; i++) {
-      touchList[i] = arguments[i];
-    }
-    touchList.length = arguments.length;
-    return touchList;
-  };
-}
-
-/**
- * create an touch point
- * @constructor
- * @param target
- * @param identifier
- * @param pos
- * @param deltaX
- * @param deltaY
- * @returns {Object} touchPoint
- */
-
-var Touch = function Touch(target, identifier, pos, deltaX, deltaY) {
-  deltaX = deltaX || 0;
-  deltaY = deltaY || 0;
-
-  this.identifier = identifier;
-  this.target = target;
-  this.clientX = pos.clientX + deltaX;
-  this.clientY = pos.clientY + deltaY;
-  this.screenX = pos.screenX + deltaX;
-  this.screenY = pos.screenY + deltaY;
-  this.pageX = pos.pageX + deltaX;
-  this.pageY = pos.pageY + deltaY;
-};
-
-/**
- * create empty touchlist with the methods
- * @constructor
- * @returns touchList
- */
-function TouchList() {
-  var touchList = [];
-
-  touchList['item'] = function(index) {
-    return this[index] || null;
-  };
-
-  // specified by Mozilla
-  touchList['identifiedTouch'] = function(id) {
-    return this[id + 1] || null;
-  };
-
-  return touchList;
-}
-
-/**
- * only trigger touches when the left mousebutton has been pressed
- * @param touchType
- * @returns {Function}
- */
-
-var initiated = false;
-function onMouse(touchType) {
-  return function(ev) {
-    // prevent mouse events
-
-    if (ev.type === 'mousedown') {
-      initiated = true;
-    }
-
-    if (ev.type === 'mouseup') {
-      initiated = false;
-    }
-
-    if (ev.type === 'mousemove' && !initiated) {
-      return;
-    }
-
-    // The EventTarget on which the touch point started when it was first placed on the surface,
-    // even if the touch point has since moved outside the interactive area of that element.
-    // also, when the target doesnt exist anymore, we update it
-    if (
-      ev.type === 'mousedown' ||
-      !eventTarget ||
-      (eventTarget && !eventTarget.dispatchEvent)
+      pageX,
+      pageY,
+      screenX,
+      screenY
     ) {
-      eventTarget = ev.target;
-    }
-
-    triggerTouch(touchType, ev);
-
-    // reset
-    if (ev.type === 'mouseup') {
-      eventTarget = null;
-    }
-  };
-}
-
-/**
- * trigger a touch event
- * @param eventName
- * @param mouseEv
- */
-function triggerTouch(eventName, mouseEv) {
-  var touchEvent = document.createEvent('Event');
-  touchEvent.initEvent(eventName, true, true);
-
-  touchEvent.altKey = mouseEv.altKey;
-  touchEvent.ctrlKey = mouseEv.ctrlKey;
-  touchEvent.metaKey = mouseEv.metaKey;
-  touchEvent.shiftKey = mouseEv.shiftKey;
-
-  touchEvent.touches = getActiveTouches(mouseEv);
-  touchEvent.targetTouches = getActiveTouches(mouseEv);
-  touchEvent.changedTouches = createTouchList(mouseEv);
-
-  eventTarget.dispatchEvent(touchEvent);
-}
-
-/**
- * create a touchList based on the mouse event
- * @param mouseEv
- * @returns {TouchList}
- */
-function createTouchList(mouseEv) {
-  var touchList = TouchList();
-  touchList.push(new Touch(eventTarget, 1, mouseEv, 0, 0));
-  return touchList;
-}
-
-/**
- * receive all active touches
- * @param mouseEv
- * @returns {TouchList}
- */
-function getActiveTouches(mouseEv) {
-  // empty list
-  if (mouseEv.type === 'mouseup') {
-    return TouchList();
+      // auto set
+      return new Touch(
+        target,
+        identifier,
+        {
+          pageX: pageX,
+          pageY: pageY,
+          screenX: screenX,
+          screenY: screenY,
+          clientX: pageX - window.pageXOffset,
+          clientY: pageY - window.pageYOffset,
+        },
+        0,
+        0
+      );
+    };
   }
-  return createTouchList(mouseEv);
-}
 
-/**
- * TouchEmulator initializer
- */
-function TouchEmulator() {
-  window.addEventListener('mousedown', onMouse('touchstart'), true);
-  window.addEventListener('mousemove', onMouse('touchmove'), true);
-  window.addEventListener('mouseup', onMouse('touchend'), true);
-}
+  if (!document.createTouchList) {
+    document.createTouchList = function () {
+      var touchList = TouchList();
+      for (var i = 0; i < arguments.length; i++) {
+        touchList[i] = arguments[i];
+      }
+      touchList.length = arguments.length;
+      return touchList;
+    };
+  }
 
-// start distance when entering the multitouch mode
-TouchEmulator['multiTouchOffset'] = 75;
+  /**
+   * create an touch point
+   * @constructor
+   * @param target
+   * @param identifier
+   * @param pos
+   * @param deltaX
+   * @param deltaY
+   * @returns {Object} touchPoint
+   */
 
-if (!supportTouch) {
-  new TouchEmulator();
-}
+  var Touch = function Touch(target, identifier, pos, deltaX, deltaY) {
+    deltaX = deltaX || 0;
+    deltaY = deltaY || 0;
+
+    this.identifier = identifier;
+    this.target = target;
+    this.clientX = pos.clientX + deltaX;
+    this.clientY = pos.clientY + deltaY;
+    this.screenX = pos.screenX + deltaX;
+    this.screenY = pos.screenY + deltaY;
+    this.pageX = pos.pageX + deltaX;
+    this.pageY = pos.pageY + deltaY;
+  };
+
+  /**
+   * create empty touchlist with the methods
+   * @constructor
+   * @returns touchList
+   */
+  function TouchList() {
+    var touchList = [];
+
+    touchList['item'] = function (index) {
+      return this[index] || null;
+    };
+
+    // specified by Mozilla
+    touchList['identifiedTouch'] = function (id) {
+      return this[id + 1] || null;
+    };
+
+    return touchList;
+  }
+
+  /**
+   * only trigger touches when the left mousebutton has been pressed
+   * @param touchType
+   * @returns {Function}
+   */
+
+  var initiated = false;
+  function onMouse(touchType) {
+    return function (ev) {
+      // prevent mouse events
+
+      if (ev.type === 'mousedown') {
+        initiated = true;
+      }
+
+      if (ev.type === 'mouseup') {
+        initiated = false;
+      }
+
+      if (ev.type === 'mousemove' && !initiated) {
+        return;
+      }
+
+      // The EventTarget on which the touch point started when it was first placed on the surface,
+      // even if the touch point has since moved outside the interactive area of that element.
+      // also, when the target doesnt exist anymore, we update it
+      if (
+        ev.type === 'mousedown' ||
+        !eventTarget ||
+        (eventTarget && !eventTarget.dispatchEvent)
+      ) {
+        eventTarget = ev.target;
+      }
+
+      triggerTouch(touchType, ev);
+
+      // reset
+      if (ev.type === 'mouseup') {
+        eventTarget = null;
+      }
+    };
+  }
+
+  /**
+   * trigger a touch event
+   * @param eventName
+   * @param mouseEv
+   */
+  function triggerTouch(eventName, mouseEv) {
+    var touchEvent = document.createEvent('Event');
+    touchEvent.initEvent(eventName, true, true);
+
+    touchEvent.altKey = mouseEv.altKey;
+    touchEvent.ctrlKey = mouseEv.ctrlKey;
+    touchEvent.metaKey = mouseEv.metaKey;
+    touchEvent.shiftKey = mouseEv.shiftKey;
+
+    touchEvent.touches = getActiveTouches(mouseEv);
+    touchEvent.targetTouches = getActiveTouches(mouseEv);
+    touchEvent.changedTouches = createTouchList(mouseEv);
+
+    eventTarget.dispatchEvent(touchEvent);
+  }
+
+  /**
+   * create a touchList based on the mouse event
+   * @param mouseEv
+   * @returns {TouchList}
+   */
+  function createTouchList(mouseEv) {
+    var touchList = TouchList();
+    touchList.push(new Touch(eventTarget, 1, mouseEv, 0, 0));
+    return touchList;
+  }
+
+  /**
+   * receive all active touches
+   * @param mouseEv
+   * @returns {TouchList}
+   */
+  function getActiveTouches(mouseEv) {
+    // empty list
+    if (mouseEv.type === 'mouseup') {
+      return TouchList();
+    }
+    return createTouchList(mouseEv);
+  }
+
+  /**
+   * TouchEmulator initializer
+   */
+  function TouchEmulator() {
+    window.addEventListener('mousedown', onMouse('touchstart'), true);
+    window.addEventListener('mousemove', onMouse('touchmove'), true);
+    window.addEventListener('mouseup', onMouse('touchend'), true);
+  }
+
+  // start distance when entering the multitouch mode
+  TouchEmulator['multiTouchOffset'] = 75;
+
+  if (!supportTouch) {
+    new TouchEmulator();
+  }
+})();