The library is getting stuck inside an infinite loop that keeps adding classes to the image

I have been trying to replace the current vannila lazy load script with this one, but I just cannot get it to work. I tried all possible combinations, even changing the attributes; the result is the same. I frankly never seen something like this, it appears as if it conflicts with something but there is really on the page that can do this.

Describe the bug The library is getting stuck inside an infinite loop that keeps adding classes to the image.

To Reproduce I cannot provide this, the configuration is plain and simple as:

<script>window.lazySizesConfig = window.lazySizesConfig || {};
// use .lazy instead of .lazyload
window.lazySizesConfig.lazyClass = 'lazy';
// use data-original instead of data-src
lazySizesConfig.srcAttr = 'data-original';
lazySizesConfig.srcsetAttr = 'data-originalSet';
lazySizesConfig.sizesAttr = 'data-originalsizes';
//page is optimized for fast onload event
lazySizesConfig.loadMode = 1;
</script>
<script>
!function(e){var t=function(u,D,f){"use strict";var k,H;if(function(){var e;var t={lazyClass:"lazyload",loadedClass:"lazyloaded",loadingClass:"lazyloading",preloadClass:"lazypreload",errorClass:"lazyerror",autosizesClass:"lazyautosizes",fastLoadedClass:"ls-is-cached",iframeLoadMode:0,srcAttr:"data-src",srcsetAttr:"data-srcset",sizesAttr:"data-sizes",minSize:40,customMedia:{},init:true,expFactor:1.5,hFac:.8,loadMode:2,loadHidden:true,ricTimeout:0,throttleDelay:125};H=u.lazySizesConfig||u.lazysizesConfig||{};for(e in t){if(!(e in H)){H[e]=t[e]}}}(),!D||!D.getElementsByClassName){return{init:function(){},cfg:H,noSupport:true}}var O=D.documentElement,i=u.HTMLPictureElement,P="addEventListener",$="getAttribute",q=u[P].bind(u),I=u.setTimeout,U=u.requestAnimationFrame||I,o=u.requestIdleCallback,j=/^picture$/i,r=["load","error","lazyincluded","_lazyloaded"],a={},G=Array.prototype.forEach,J=function(e,t){if(!a[t]){a[t]=new RegExp("(\s|^)"+t+"(\s|$)")}return a[t].test(e[$]("class")||"")&&a[t]},K=function(e,t){if(!J(e,t)){e.setAttribute("class",(e[$]("class")||"").trim()+" "+t)}},Q=function(e,t){var a;if(a=J(e,t)){e.setAttribute("class",(e[$]("class")||"").replace(a," "))}},V=function(t,a,e){var i=e?P:"removeEventListener";if(e){V(t,a)}r.forEach(function(e){t[i](e,a)})},X=function(e,t,a,i,r){var n=D.createEvent("Event");if(!a){a={}}a.instance=k;n.initEvent(t,!i,!r);n.detail=a;e.dispatchEvent(n);return n},Y=function(e,t){var a;if(!i&&(a=u.picturefill||H.pf)){if(t&&t.src&&!e[$]("srcset")){e.setAttribute("srcset",t.src)}a({reevaluate:true,elements:[e]})}else if(t&&t.src){e.src=t.src}},Z=function(e,t){return(getComputedStyle(e,null)||{})[t]},s=function(e,t,a){a=a||e.offsetWidth;while(a<H.minSize&&t&&!e._lazysizesWidth){a=t.offsetWidth;t=t.parentNode}return a},ee=function(){var a,i;var t=[];var r=[];var n=t;var s=function(){var e=n;n=t.length?r:t;a=true;i=false;while(e.length){e.shift()()}a=false};var e=function(e,t){if(a&&!t){e.apply(this,arguments)}else{n.push(e);if(!i){i=true;(D.hidden?I:U)(s)}}};e._lsFlush=s;return e}(),te=function(a,e){return e?function(){ee(a)}:function(){var e=this;var t=arguments;ee(function(){a.apply(e,t)})}},ae=function(e){var a;var i=0;var r=H.throttleDelay;var n=H.ricTimeout;var t=function(){a=false;i=f.now();e()};var s=o&&n>49?function(){o(t,{timeout:n});if(n!==H.ricTimeout){n=H.ricTimeout}}:te(function(){I(t)},true);return function(e){var t;if(e=e===true){n=33}if(a){return}a=true;t=r-(f.now()-i);if(t<0){t=0}if(e||t<9){s()}else{I(s,t)}}},ie=function(e){var t,a;var i=99;var r=function(){t=null;e()};var n=function(){var e=f.now()-a;if(e<i){I(n,i-e)}else{(o||r)(r)}};return function(){a=f.now();if(!t){t=I(n,i)}}},e=function(){var v,m,c,h,e;var y,z,g,p,C,b,A;var n=/^img$/i;var d=/^iframe$/i;var E="onscroll"in u&&!/(gle|ing)bot/.test(navigator.userAgent);var _=0;var w=0;var M=0;var N=-1;var L=function(e){M--;if(!e||M<0||!e.target){M=0}};var x=function(e){if(A==null){A=Z(D.body,"visibility")=="hidden"}return A||!(Z(e.parentNode,"visibility")=="hidden"&&Z(e,"visibility")=="hidden")};var W=function(e,t){var a;var i=e;var r=x(e);g-=t;b+=t;p-=t;C+=t;while(r&&(i=i.offsetParent)&&i!=D.body&&i!=O){r=(Z(i,"opacity")||1)>0;if(r&&Z(i,"overflow")!="visible"){a=i.getBoundingClientRect();r=C>a.left&&p<a.right&&b>a.top-1&&g<a.bottom+1}}return r};var t=function(){var e,t,a,i,r,n,s,o,l,u,f,c;var d=k.elements;if((h=H.loadMode)&&M<8&&(e=d.length)){t=0;N++;for(;t<e;t++){if(!d[t]||d[t]._lazyRace){continue}if(!E||k.prematureUnveil&&k.prematureUnveil(d[t])){R(d[t]);continue}if(!(o=d[t][$]("data-expand"))||!(n=o*1)){n=w}if(!u){u=!H.expand||H.expand<1?O.clientHeight>500&&O.clientWidth>500?500:370:H.expand;k._defEx=u;f=u*H.expFactor;c=H.hFac;A=null;if(w<f&&M<1&&N>2&&h>2&&!D.hidden){w=f;N=0}else if(h>1&&N>1&&M<6){w=u}else{w=_}}if(l!==n){y=innerWidth+n*c;z=innerHeight+n;s=n*-1;l=n}a=d[t].getBoundingClientRect();if((b=a.bottom)>=s&&(g=a.top)<=z&&(C=a.right)>=s*c&&(p=a.left)<=y&&(b||C||p||g)&&(H.loadHidden||x(d[t]))&&(m&&M<3&&!o&&(h<3||N<4)||W(d[t],n))){R(d[t]);r=true;if(M>9){break}}else if(!r&&m&&!i&&M<4&&N<4&&h>2&&(v[0]||H.preloadAfterLoad)&&(v[0]||!o&&(b||C||p||g||d[t][$](H.sizesAttr)!="auto"))){i=v[0]||d[t]}}if(i&&!r){R(i)}}};var a=ae(t);var S=function(e){var t=e.target;if(t._lazyCache){delete t._lazyCache;return}L(e);K(t,H.loadedClass);Q(t,H.loadingClass);V(t,B);X(t,"lazyloaded")};var i=te(S);var B=function(e){i({target:e.target})};var T=function(e,t){var a=e.getAttribute("data-load-mode")||H.iframeLoadMode;if(a==0){e.contentWindow.location.replace(t)}else if(a==1){e.src=t}};var F=function(e){var t;var a=e[$](H.srcsetAttr);if(t=H.customMedia[e[$]("data-media")||e[$]("media")]){e.setAttribute("media",t)}if(a){e.setAttribute("srcset",a)}};var s=te(function(t,e,a,i,r){var n,s,o,l,u,f;if(!(u=X(t,"lazybeforeunveil",e)).defaultPrevented){if(i){if(a){K(t,H.autosizesClass)}else{t.setAttribute("sizes",i)}}s=t[$](H.srcsetAttr);n=t[$](H.srcAttr);if(r){o=t.parentNode;l=o&&j.test(o.nodeName||"")}f=e.firesLoad||"src"in t&&(s||n||l);u={target:t};K(t,H.loadingClass);if(f){clearTimeout(c);c=I(L,2500);V(t,B,true)}if(l){G.call(o.getElementsByTagName("source"),F)}if(s){t.setAttribute("srcset",s)}else if(n&&!l){if(d.test(t.nodeName)){T(t,n)}else{t.src=n}}if(r&&(s||l)){Y(t,{src:n})}}if(t._lazyRace){delete t._lazyRace}Q(t,H.lazyClass);ee(function(){var e=t.complete&&t.naturalWidth>1;if(!f||e){if(e){K(t,H.fastLoadedClass)}S(u);t._lazyCache=true;I(function(){if("_lazyCache"in t){delete t._lazyCache}},9)}if(t.loading=="lazy"){M--}},true)});var R=function(e){if(e._lazyRace){return}var t;var a=n.test(e.nodeName);var i=a&&(e[$](H.sizesAttr)||e[$]("sizes"));var r=i=="auto";if((r||!m)&&a&&(e[$]("src")||e.srcset)&&!e.complete&&!J(e,H.errorClass)&&J(e,H.lazyClass)){return}t=X(e,"lazyunveilread").detail;if(r){re.updateElem(e,true,e.offsetWidth)}e._lazyRace=true;M++;s(e,t,r,i,a)};var r=ie(function(){H.loadMode=3;a()});var o=function(){if(H.loadMode==3){H.loadMode=2}r()};var l=function(){if(m){return}if(f.now()-e<999){I(l,999);return}m=true;H.loadMode=3;a();q("scroll",o,true)};return{_:function(){e=f.now();k.elements=D.getElementsByClassName(H.lazyClass);v=D.getElementsByClassName(H.lazyClass+" "+H.preloadClass);q("scroll",a,true);q("resize",a,true);q("pageshow",function(e){if(e.persisted){var t=D.querySelectorAll("."+H.loadingClass);if(t.length&&t.forEach){U(function(){t.forEach(function(e){if(e.complete){R(e)}})})}}});if(u.MutationObserver){new MutationObserver(a).observe(O,{childList:true,subtree:true,attributes:true})}else{O[P]("DOMNodeInserted",a,true);O[P]("DOMAttrModified",a,true);setInterval(a,999)}q("hashchange",a,true);["focus","mouseover","click","load","transitionend","animationend"].forEach(function(e){D[P](e,a,true)});if(/d$|^c/.test(D.readyState)){l()}else{q("load",l);D[P]("DOMContentLoaded",a);I(l,2e4)}if(k.elements.length){t();ee._lsFlush()}else{a()}},checkElems:a,unveil:R,_aLSL:o}}(),re=function(){var a;var n=te(function(e,t,a,i){var r,n,s;e._lazysizesWidth=i;i+="px";e.setAttribute("sizes",i);if(j.test(t.nodeName||"")){r=t.getElementsByTagName("source");for(n=0,s=r.length;n<s;n++){r[n].setAttribute("sizes",i)}}if(!a.detail.dataAttr){Y(e,a.detail)}});var i=function(e,t,a){var i;var r=e.parentNode;if(r){a=s(e,r,a);i=X(e,"lazybeforesizes",{width:a,dataAttr:!!t});if(!i.defaultPrevented){a=i.detail.width;if(a&&a!==e._lazysizesWidth){n(e,r,i,a)}}}};var e=function(){var e;var t=a.length;if(t){e=0;for(;e<t;e++){i(a[e])}}};var t=ie(e);return{_:function(){a=D.getElementsByClassName(H.autosizesClass);q("resize",t)},checkElems:t,updateElem:i}}(),t=function(){if(!t.i&&D.getElementsByClassName){t.i=true;re._();e._()}};return I(function(){H.init&&t()}),k={cfg:H,autoSizer:re,loader:e,init:t,uP:Y,aC:K,rC:Q,hC:J,fire:X,gW:s,rAF:ee}}(e,e.document,Date);e.lazySizes=t,"object"==typeof module&&module.exports&&(module.exports=t)}("undefined"!=typeof window?window:{});
</script>

The above is inserted at the end of the document (just before the closing body tag).

The image tag:

<img width="1400px" height="160px"
          src="..."
          srcset="data:image/gif;base64,R0lGODlhAQABAAAAACH5BAEKAAEALAAAAAABAAEAAAICTAEAOw=="
          data-originalsizes="auto"
          data-originalSet="... 320w, ... 576w"
          class="page-header-image lazy"
      alt="..." />

Steps to reproduce the behavior: I have no idea how you can reproduce, try to use the above.

What is the expected behavior: Lazy loading without such bug!?

What happened instead: An infinite loop that keeps adding classes to the image. Result:

In what environment (browser/device etc.) does this bug happen/not happen: Latest Chrome.

Keywords help others to find this issue:

⚠️ Search for existing open/closed issues/discussions before you report the issue. ⚠️ If you do not provide enough information to reproduce your bug. We won't be able to work on the issue. In most cases just providing a fraction of your code is not enough!

aFarkas / lazysizes

The library is getting stuck inside an infinite loop that keeps adding classes to the image #954