How do I bind this into a socket.on call?

class SocketManager {
    constructor( ) {
        this.test = 'Test string';
        
        this._Initialize( );
    }
    
    this._Initialize( ) {
        this.socket = io.connect( );
        
        this.socket.on( 'test', ( ) => {
            console.log( this.test ); // Wanted Output: "Test string"
        } );
    }
}