diff --git a/dist/vue2-waterfall.js b/dist/vue2-waterfall.js
index 7c23fcc..62b5bf7 100644
--- a/dist/vue2-waterfall.js
+++ b/dist/vue2-waterfall.js
@@ -1,6 +1,6 @@
 /*!
  * An AutoHeight Waterfall Component For Vue2
- * v3.0.1 ©2020 PLDaily <pcd12321@gmail.com>
+ * v3.0.1 ©2021 PLDaily <pcd12321@gmail.com>
  * https://github.com/PLDaily/vue2-waterfall#readme
  */
 !function(t,e){"object"==typeof exports&&"object"==typeof module?module.exports=e():"function"==typeof define&&define.amd?define([],e):"object"==typeof exports?exports.Vue2Waterfall=e():t.Vue2Waterfall=e()}("undefined"!=typeof self?self:this,function(){return function(t){function e(n){if(i[n])return i[n].exports;var o=i[n]={i:n,l:!1,exports:{}};return t[n].call(o.exports,o,o.exports,e),o.l=!0,o.exports}var i={};return e.m=t,e.c=i,e.d=function(t,i,n){e.o(t,i)||Object.defineProperty(t,i,{configurable:!1,enumerable:!0,get:n})},e.n=function(t){var i=t&&t.__esModule?function(){return t.default}:function(){return t};return e.d(i,"a",i),i},e.o=function(t,e){return Object.prototype.hasOwnProperty.call(t,e)},e.p="/",e(e.s=5)}([function(t,e,i){var n,o;!function(r,s){n=s,void 0!==(o="function"==typeof n?n.call(e,i,e,t):n)&&(t.exports=o)}("undefined"!=typeof window&&window,function(){"use strict";function t(){}var e=t.prototype;return e.on=function(t,e){if(t&&e){var i=this._events=this._events||{},n=i[t]=i[t]||[];return-1==n.indexOf(e)&&n.push(e),this}},e.once=function(t,e){if(t&&e){this.on(t,e);var i=this._onceEvents=this._onceEvents||{};return(i[t]=i[t]||{})[e]=!0,this}},e.off=function(t,e){var i=this._events&&this._events[t];if(i&&i.length){var n=i.indexOf(e);return-1!=n&&i.splice(n,1),this}},e.emitEvent=function(t,e){var i=this._events&&this._events[t];if(i&&i.length){i=i.slice(0),e=e||[];for(var n=this._onceEvents&&this._onceEvents[t],o=0;o<i.length;o++){var r=i[o];n&&n[r]&&(this.off(t,r),delete n[r]),r.apply(this,e)}return this}},e.allOff=function(){delete this._events,delete this._onceEvents},t})},function(t,e,i){var n,o;/*!
@@ -8,7 +8,7 @@
  * measure size of elements
  * MIT license
  */
-!function(r,s){n=s,void 0!==(o="function"==typeof n?n.call(e,i,e,t):n)&&(t.exports=o)}(window,function(){"use strict";function t(t){var e=parseFloat(t);return-1==t.indexOf("%")&&!isNaN(e)&&e}function e(){}function i(){for(var t={width:0,height:0,innerWidth:0,innerHeight:0,outerWidth:0,outerHeight:0},e=0;e<u;e++){t[h[e]]=0}return t}function n(t){var e=getComputedStyle(t);return e||a("Style returned "+e+". Are you running this code in a hidden iframe on Firefox? See https://bit.ly/getsizebug1"),e}function o(){if(!d){d=!0;var e=document.createElement("div");e.style.width="200px",e.style.padding="1px 2px 3px 4px",e.style.borderStyle="solid",e.style.borderWidth="1px 2px 3px 4px",e.style.boxSizing="border-box";var i=document.body||document.documentElement;i.appendChild(e);var o=n(e);s=200==Math.round(t(o.width)),r.isBoxSizeOuter=s,i.removeChild(e)}}function r(e){if(o(),"string"==typeof e&&(e=document.querySelector(e)),e&&"object"==typeof e&&e.nodeType){var r=n(e);if("none"==r.display)return i();var a={};a.width=e.offsetWidth,a.height=e.offsetHeight;for(var d=a.isBorderBox="border-box"==r.boxSizing,l=0;l<u;l++){var c=h[l],f=r[c],p=parseFloat(f);a[c]=isNaN(p)?0:p}var m=a.paddingLeft+a.paddingRight,g=a.paddingTop+a.paddingBottom,v=a.marginLeft+a.marginRight,y=a.marginTop+a.marginBottom,_=a.borderLeftWidth+a.borderRightWidth,E=a.borderTopWidth+a.borderBottomWidth,b=d&&s,I=t(r.width);!1!==I&&(a.width=I+(b?0:m+_));var x=t(r.height);return!1!==x&&(a.height=x+(b?0:g+E)),a.innerWidth=a.width-(m+_),a.innerHeight=a.height-(g+E),a.outerWidth=a.width+v,a.outerHeight=a.height+y,a}}var s,a="undefined"==typeof console?e:function(t){console.error(t)},h=["paddingLeft","paddingRight","paddingTop","paddingBottom","marginLeft","marginRight","marginTop","marginBottom","borderLeftWidth","borderRightWidth","borderTopWidth","borderBottomWidth"],u=h.length,d=!1;return r})},function(t,e){t.exports=function(t,e,i,n,o,r){var s,a=t=t||{},h=typeof t.default;"object"!==h&&"function"!==h||(s=t,a=t.default);var u="function"==typeof a?a.options:a;e&&(u.render=e.render,u.staticRenderFns=e.staticRenderFns,u._compiled=!0),i&&(u.functional=!0),o&&(u._scopeId=o);var d;if(r?(d=function(t){t=t||this.$vnode&&this.$vnode.ssrContext||this.parent&&this.parent.$vnode&&this.parent.$vnode.ssrContext,t||"undefined"==typeof __VUE_SSR_CONTEXT__||(t=__VUE_SSR_CONTEXT__),n&&n.call(this,t),t&&t._registeredComponents&&t._registeredComponents.add(r)},u._ssrRegister=d):n&&(d=n),d){var l=u.functional,c=l?u.render:u.beforeCreate;l?(u._injectStyles=d,u.render=function(t,e){return d.call(e),c(t,e)}):u.beforeCreate=c?[].concat(c,d):[d]}return{esModule:s,exports:a,options:u}}},function(t,e,i){"use strict";Object.defineProperty(e,"__esModule",{value:!0});var n="undefined"!=typeof window,o=n?window.Masonry||i(7):null,r=n?i(12):null;e.default={name:"Waterfall",props:{options:{type:Object,default:{}}},mounted:function(){this.initializeMasonry(),this.imagesLoaded()},updated:function(){this.performLayout(),this.imagesLoaded()},unmounted:function(){this.masonry.destroy()},methods:{imagesLoaded:function(){var t=this,e=this.$refs.waterfall;r(e,function(){t.masonry.layout()})},performLayout:function(){var t=this.diffDomChildren();t.removed.length>0&&(this.masonry.remove(t.removed),this.masonry.reloadItems()),t.appended.length>0&&(this.masonry.appended(t.appended),this.masonry.reloadItems()),t.prepended.length>0&&this.masonry.prepended(t.prepended),t.moved.length>0&&this.masonry.reloadItems(),this.masonry.layout()},diffDomChildren:function(){var t=this.domChildren.filter(function(t){return!!t.parentNode}),e=this.getNewDomChildren(),i=t.filter(function(t){return!e.includes(t)}),n=e.filter(function(e){return!t.includes(e)}),o=n.filter(function(t,i){return e[i]===t}),r=n.filter(function(t){return!o.includes(t)}),s=[];return 0===i.length&&(s=t.filter(function(t,i){return i!==e.indexOf(t)})),this.domChildren=e,{old:t,new:e,removed:i,appended:r,prepended:o,moved:s}},initializeMasonry:function(){this.masonry||(this.masonry=new o(this.$refs.waterfall,this.options),this.domChildren=this.getNewDomChildren())},getNewDomChildren:function(){var t=this.$refs.waterfall,e=this.options&&this.options.itemSelector?t.querySelectorAll(this.options.itemSelector):t.children;return Array.prototype.slice.call(e)}}}},function(t,e,i){"use strict";Object.defineProperty(e,"__esModule",{value:!0}),e.default={name:"WaterfallItem"}},function(t,e,i){"use strict";function n(t){return t&&t.__esModule?t:{default:t}}Object.defineProperty(e,"__esModule",{value:!0}),e.WaterfallItem=e.Waterfall=void 0;var o=i(6),r=n(o),s=i(14),a=n(s);e.Waterfall=r.default,e.WaterfallItem=a.default},function(t,e,i){"use strict";Object.defineProperty(e,"__esModule",{value:!0});var n=i(3),o=i.n(n);for(var r in n)"default"!==r&&function(t){i.d(e,t,function(){return n[t]})}(r);var s=i(13),a=i(2),h=a(o.a,s.a,!1,null,null,null);h.options.__file="src/Waterfall.vue",e.default=h.exports},function(t,e,i){var n,o,r;/*!
+!function(r,s){n=s,void 0!==(o="function"==typeof n?n.call(e,i,e,t):n)&&(t.exports=o)}(window,function(){"use strict";function t(t){var e=parseFloat(t);return-1==t.indexOf("%")&&!isNaN(e)&&e}function e(){}function i(){for(var t={width:0,height:0,innerWidth:0,innerHeight:0,outerWidth:0,outerHeight:0},e=0;e<u;e++){t[h[e]]=0}return t}function n(t){var e=getComputedStyle(t);return e||a("Style returned "+e+". Are you running this code in a hidden iframe on Firefox? See https://bit.ly/getsizebug1"),e}function o(){if(!d){d=!0;var e=document.createElement("div");e.style.width="200px",e.style.padding="1px 2px 3px 4px",e.style.borderStyle="solid",e.style.borderWidth="1px 2px 3px 4px",e.style.boxSizing="border-box";var i=document.body||document.documentElement;i.appendChild(e);var o=n(e);s=200==Math.round(t(o.width)),r.isBoxSizeOuter=s,i.removeChild(e)}}function r(e){if(o(),"string"==typeof e&&(e=document.querySelector(e)),e&&"object"==typeof e&&e.nodeType){var r=n(e);if("none"==r.display)return i();var a={};a.width=e.offsetWidth,a.height=e.offsetHeight;for(var d=a.isBorderBox="border-box"==r.boxSizing,l=0;l<u;l++){var c=h[l],f=r[c],p=parseFloat(f);a[c]=isNaN(p)?0:p}var m=a.paddingLeft+a.paddingRight,g=a.paddingTop+a.paddingBottom,v=a.marginLeft+a.marginRight,y=a.marginTop+a.marginBottom,_=a.borderLeftWidth+a.borderRightWidth,E=a.borderTopWidth+a.borderBottomWidth,b=d&&s,I=t(r.width);!1!==I&&(a.width=I+(b?0:m+_));var x=t(r.height);return!1!==x&&(a.height=x+(b?0:g+E)),a.innerWidth=a.width-(m+_),a.innerHeight=a.height-(g+E),a.outerWidth=a.width+v,a.outerHeight=a.height+y,a}}var s,a="undefined"==typeof console?e:function(t){console.error(t)},h=["paddingLeft","paddingRight","paddingTop","paddingBottom","marginLeft","marginRight","marginTop","marginBottom","borderLeftWidth","borderRightWidth","borderTopWidth","borderBottomWidth"],u=h.length,d=!1;return r})},function(t,e){t.exports=function(t,e,i,n,o,r){var s,a=t=t||{},h=typeof t.default;"object"!==h&&"function"!==h||(s=t,a=t.default);var u="function"==typeof a?a.options:a;e&&(u.render=e.render,u.staticRenderFns=e.staticRenderFns,u._compiled=!0),i&&(u.functional=!0),o&&(u._scopeId=o);var d;if(r?(d=function(t){t=t||this.$vnode&&this.$vnode.ssrContext||this.parent&&this.parent.$vnode&&this.parent.$vnode.ssrContext,t||"undefined"==typeof __VUE_SSR_CONTEXT__||(t=__VUE_SSR_CONTEXT__),n&&n.call(this,t),t&&t._registeredComponents&&t._registeredComponents.add(r)},u._ssrRegister=d):n&&(d=n),d){var l=u.functional,c=l?u.render:u.beforeCreate;l?(u._injectStyles=d,u.render=function(t,e){return d.call(e),c(t,e)}):u.beforeCreate=c?[].concat(c,d):[d]}return{esModule:s,exports:a,options:u}}},function(t,e,i){"use strict";Object.defineProperty(e,"__esModule",{value:!0});var n="undefined"!=typeof window,o=n?window.Masonry||i(7):null,r=n?i(12):null;e.default={name:"Waterfall",props:{options:{type:Object,default:function(){}}},mounted:function(){this.initializeMasonry(),this.imagesLoaded()},updated:function(){this.performLayout(),this.imagesLoaded()},unmounted:function(){this.masonry.destroy()},methods:{imagesLoaded:function(){var t=this,e=this.$refs.waterfall;r(e,function(){t.masonry.layout()})},performLayout:function(){var t=this.diffDomChildren();t.removed.length>0&&(this.masonry.remove(t.removed),this.masonry.reloadItems()),t.appended.length>0&&(this.masonry.appended(t.appended),this.masonry.reloadItems()),t.prepended.length>0&&this.masonry.prepended(t.prepended),t.moved.length>0&&this.masonry.reloadItems(),this.masonry.layout()},diffDomChildren:function(){var t=this.domChildren.filter(function(t){return!!t.parentNode}),e=this.getNewDomChildren(),i=t.filter(function(t){return!e.includes(t)}),n=e.filter(function(e){return!t.includes(e)}),o=n.filter(function(t,i){return e[i]===t}),r=n.filter(function(t){return!o.includes(t)}),s=[];return 0===i.length&&(s=t.filter(function(t,i){return i!==e.indexOf(t)})),this.domChildren=e,{old:t,new:e,removed:i,appended:r,prepended:o,moved:s}},initializeMasonry:function(){this.masonry||(this.masonry=new o(this.$refs.waterfall,this.options),this.domChildren=this.getNewDomChildren())},getNewDomChildren:function(){var t=this.$refs.waterfall,e=this.options&&this.options.itemSelector?t.querySelectorAll(this.options.itemSelector):t.children;return Array.prototype.slice.call(e)}}}},function(t,e,i){"use strict";Object.defineProperty(e,"__esModule",{value:!0}),e.default={name:"WaterfallItem"}},function(t,e,i){"use strict";function n(t){return t&&t.__esModule?t:{default:t}}Object.defineProperty(e,"__esModule",{value:!0}),e.WaterfallItem=e.Waterfall=void 0;var o=i(6),r=n(o),s=i(14),a=n(s);e.Waterfall=r.default,e.WaterfallItem=a.default},function(t,e,i){"use strict";Object.defineProperty(e,"__esModule",{value:!0});var n=i(3),o=i.n(n);for(var r in n)"default"!==r&&function(t){i.d(e,t,function(){return n[t]})}(r);var s=i(13),a=i(2),h=a(o.a,s.a,!1,null,null,null);h.options.__file="src/Waterfall.vue",e.default=h.exports},function(t,e,i){var n,o,r;/*!
  * Masonry v4.2.2
  * Cascading grid layout library
  * https://masonry.desandro.com
diff --git a/src/Waterfall.vue b/src/Waterfall.vue
index 55cca97..c61a38e 100644
--- a/src/Waterfall.vue
+++ b/src/Waterfall.vue
@@ -12,7 +12,7 @@ export default {
   props: {
     options: {
       type: Object,
-      default: {}
+      default: () => {}
     }
   },
   mounted () {