How to use the @iconify/iconify.iconExists function in @iconify/iconify

render() {
		let props = this.props,
			name = props.name,
			loaded = Iconify.iconExists(name),
			deleteButton = null;

		// Delete button
		if (props.view.type === 'custom' && props.view.canDelete) {
			deleteButton = (
				<a title="{lang.delete}" href="#">
					
				</a>
			);
		}

render() {
		let props = this.props,
			name = props.name,
			icon = props.icon,
			loaded = Iconify.iconExists(name);

		// Generate link and tooltip
		let link = props.config.links.icon
			.replace('{prefix}', icon.prefix)
			.replace('{name}', icon.name);

		if (!loaded) {
			return (
				
			);

render() {
		let app = this.props.app,
			iconName = app.options.iconName;

		// No icon selected - render SimpleFooter
		if (iconName === null) {
			return ;
		}

		// Check if icon has been loaded
		if (!Iconify.iconExists(iconName)) {
			Iconify.preloadImages([iconName]);
			if (!this._listener) {
				this._listener = this._onIconsLoaded.bind(this);
				document.addEventListener('IconifyAddedIcons', this._listener, true);
			}
			return ;
		}

		// Loaded
		return ;
	}

counter => {
		// Do not delay for more than 1 second
		return counter > 10 || Iconify.iconExists('mdi:account-check');
	},
	() => {

			icon => !Iconify.iconExists(icon.prefix + ':' + icon.name)
		);