Please document how to reference a list of items

Please document how to use forwardRef (the preferred way) to retrieve a list or array of items. For example,

const foo = React.forwardRef( (props,ref) => 
  props.superHeros.map( 
    ( hero, index) => <li ref={  ref  } key={ index }>{ hero }</li>
  ) 
)

Perhaps the key question here is, why not do this?

componentDidMount(){
  const foo = this.refs.root.querySelector('.foo')
  ...
}

Suppose there are 50,000 className='foo' elements that are returned by an embedded component. Is this code not portable? Is this code slower than having 50,000 ref created?

Please document this.

Comece com o exemplo de forwardRef na issue e compare-o com a abordagem componentDidMount/querySelector. Documente como referenciar uma lista ou array de itens, incluindo as questões de portabilidade e desempenho levantadas sobre muitos elementos. Considera-se concluído quando a abordagem preferida e seus trade-offs estiverem claramente explicados.