example.js

    @autobind
    onClick(e: SyntheticEvent): void {
        e.preventDefault();
        const elTarget = e.currentTarget;
        if (elTarget instanceof HTMLElement) {
            const classList = elTarget.classList;

            // only allow steps that are in the past or have errors to be edited
            if (classList.contains('c--past') || classList.contains('c--error')) {
                const stepID = parseInt(`${elTarget.dataset.id}`, 10);
                this.props.onSelectStep(stepID);
            }
        }
    }