react native conditional rendering

Question

I am trying to use an inline if statement to check if a piece of data exists and if it does to display it. this code is currently sitting in my render, return block.

the problem I am having is that using this, the content is no longer being rendered

{(() => {
              if (this.props.data.size) {
                <Text style={styles.headerLabel}>Sizes</Text>
                {(this.props.data.size||[]).map((section,i) => (
                  <AddToCartRow key={i} data={section} productName={this.props.data.name} value={Config.priceToPriceWithCurrency(section.price)} />
                ))}
              }
            })()}

Answer 1

This below code also check empty string.

render(){
  return(
    <View>
    {!!this.state.error && <Text>{this.state.errorMessage}</Text>}
    </View>
  );
}

Answer 2

render(){
  return(
    <View>
      {this.state.error && <Text style={{ color: 'red' }}>{this.state.errorMessage}</Text>}
      <Text>Hello World!</Text>
    </View>
  );
}

There you go.