javascript - React, setState warning for mounted/unmounted component -

i have react component using load images progressively app has been working great me. when use on page load images, though, seeing error:

warning.js:35 warning: setstate(...): can update mounted or mounting component. means called setstate() on unmounted component. no-op.

multiple times - looks once each image called. not seem effecting image components still work. wondering how rid of error though, cannot figure out how.

so here component:

import react, { proptypes } 'react';  require('./progressive-image.scss');  export default class progressiveimage extends react.component {   constructor(props) {     super(props);      this.state = {       loaded: false,       image: props.smallimg     };      this.loadimage = this.loadimage.bind(this);     this.onload = this.onload.bind(this);     this.onerror = this.onerror.bind(this);     this.image = undefined;   }    componentdidmount() {     const { largeimg } = this.props;     this.loadimage(largeimg);   }    onerror(err) {     console.warn('error loading progressive image :', err);   }    onload() {     this.setstate({       loaded: true,       image: this.image.src     });   }    componentdidupdate(nextprops) {     const { largeimg, smallimg } = nextprops;      if (largeimg !== this.props.largeimg) {       this.setstate({ loaded: false, image: smallimg }, () => {         this.loadimage(largeimg);       });     }   }     loadimage(src) {     if (this.image) {       this.image.onload = null;       this.image.onerror = null;     }      const image = new image();     this.image = image;     image.onload = this.onload;     image.onerror = this.onerror;     image.src = src;   }    render() {     const imgstyle = { 'paddingbottom': this.props.heightratio };     const { imgalt, imgtitle } = this.props;      return (       <div classname={`progressive-placeholder ${this.state.loaded ? 'loaded' : ''}`}>         {this.state.loaded &&           <img             alt={imgalt}             classname={`loaded`}             src={this.state.image}             title={imgtitle}              />         }         <img classname={`img-small ${!this.state.loaded ? 'loaded' : ''}`} src={this.state.image} alt="placeholder image loading"/>         <div style={imgstyle} ></div>       </div>     );   } }  progressiveimage.displayname = 'progressiveimage';  progressiveimage.proptypes = {   bgcolor: proptypes.string,   heightratio: proptypes.string.isrequired,   largeimg: proptypes.string.isrequired,   smallimg: proptypes.string.isrequired,   imgalt: proptypes.string,   imgtitle: proptypes.string, }; 

so time setstate called when onloador componentdidupdate called. thinking because called did mount , did update should not getting error. looking insight on how clean error, has me puzzled. if additional info needed, happy provide.

the problem callback in image.onload called @ any random point:

    image.onload = this.onload; 

chances this.onload being called while component rendering.

the problem because this.onload called when external image resource loads when doing this.setstate, component rendering , this cause error.

to handle recommend setting loaded/image values outside of local component state , instead dispatch global state using redux.

wiki