plugin improvement – wp.media Uncaught TypeError: Can’t learn properties of undefined (studying ‘state’)

Right here in a JS class, I used “wp.media” to add photographs. I can open the media popup by clicking a button. However getting this error (Uncaught TypeError: Can’t learn properties of undefined (studying ‘state’)) whereas submitting the picture.

    constructor ( btn ) {
        tremendous();
        this.uploaderBtn = $( btn );
        this.mediaFrame;

        this.occasions();
    }

    occasions () {
        this.uploaderBtn.on( 'click on', this.add.bind( this ) );
    }

    add ( e ) {
        e.preventDefault();
        //If the uploader object has already been created, reopen the dialog
        if ( this.mediaFrame ) {
          this.mediaFrame.open();
          return;
        }

        //Prolong the wp.media object
        this.mediaFrame = wp.media.frames.file_frame = wp.media({
          title: 'Select Picture',
          button: {
            textual content: 'Select Picture'
          },
          a number of: true
        });

        this.mediaFrame.on('choose', perform() {
            const choice = this.mediaFrame.state().get('choice');
            console.log( choice );
        });

        this.mediaFrame.open();
    }