Jammming Error


Please can someone help me with the error pictured? As I do not understand how this is undefined. I’m by no means an expert, but this one is beyond me. Code as below, thank you very much.

TrackList.js

import React from ‘react’;
import ‘./TrackList.css’;
import Track from ‘…/Track/Track’;

class TrackList extends React.Component {
render() {
return(

{
     this.props.track.map(track => {
	
	return <Track track={track} key={track.id} 
	onRemove={this.props.onRemove} isRemoval={true} />
}

)

}

</div>

);
}

};

export default TrackList;

Track.js

import React from ‘react’;
import ‘./Track.css’;

class Track extends React.Component {
constructor(props){
super(props);
this.addTrack = this.addTrack.bind(this);
this.removeTrack =this.removeTrack.bind(this);
}

renderAction() {
if(this.props.isRemoval) {
return -
} else {
return +
}

}

addTrack() {
this.props.onAdd(this.props.track);
}

removeTrack() {
this.props.onRemove(this.props.track);
}

render() {
	return(

{this.props.track.name}

{this.props.track.artist} | {this.props.track.album}

{this.renderAction()}
)
}

};

export default Track;