mangocaptain mangocaptain - 6 months ago 26
React JSX Question

Check truthiness of props passed from mapStateToProps in functional react redux component

I have 3 components, TypeList, ConnectedType (

), and Type. Type will receive props from both TypeList (
onClick, name
) passing props to ConnectedType as well as ConnectedType's mapStateToProps (
onMiniPokemonClick, miniPokemon
). How do I do a check to see if
exists before mapping it out? Is it possible to do logic on a functional component or do I have to make it a class and create a helper function inside?

const Type = ({onClick, name, onMiniPokemonClick, miniPokemon}) => (
if (miniPokemon) { (pokemon, idx) {
return (<MiniPokemon onClick={() => onMiniPokemonClick(} name={}/>)


All you need to do is use brackets to allow a multiline function body

const Type = ({onClick, name, onMiniPokemonClick, miniPokemon}) => {
   // some logic   
   return (

Or if you just need to ensure that miniPokemon is an array when a null/undefined value comes through - you could supply a default argument:

({onClick, name, onMiniPokemonClick, miniPokemon = []})