How to pass picker data into API in React Native

Question

I built a React Native Component that lets you choose several types of beers and it will render into a listview with picker.

The problem I am having trouble grasping is sending that data into the BreweryDb Api. I am not sure where to start with this semi completed component.

import React, { Component } from 'react';
import { View, Text, Picker, StyleSheet, ListView } from 'react-native'

const ds = new ListView.DataSource({rowHasChanged: (row1, row2) => row1 !== row2});

export default class BeerPicker extends Component {
    constructor(props){
      super(props);

      this.state = {
        beer: [],
        beerDataSource: ds.cloneWithRows([]),
        dataSource: ds.cloneWithRows(['string1', 'string2', 'string3']), //It seems to be not needed...
        items: [
          {label: 'Choose Beer', value: 'none'}, 
          {label: 'IPA', value: 'ipa'}, 
          {label: 'Pilsner', value: 'pilsner'}, 
          {label: 'Stout', value: 'stout'}
        ],
        selectedItem: 'none'
      };

      this.addBeer = this.addBeer.bind(this);
    }

    addBeer(itemValue, itemIndex){ 
      let newBeerArray = [...this.state.beer, itemValue];
      this.setState({
        beer: newBeerArray,
        selectedItem: itemValue,
        beerDataSource: ds.cloneWithRows(newBeerArray),
      });
    }

    renderRow(data) {
      return (
        <Text>{`\u2022 ${data}`}</Text>
      );
    }

    render() {
      let items = this.state.items.map((item, index) => {
        return (<Picker.item label={item.label} value={item.value} key={index}/>);
      });

      return (
        <View>
          <Picker selectedValue={this.state.selectedItem} onValueChange = {this.addBeer}>
            {items}
          </Picker>
          <ListView
            dataSource={this.state.beerDataSource}
            renderRow={this.renderRow}/>
        </View>
      )
    }
}

const styles = StyleSheet.create({
   text: {
      fontSize: 30,
      alignSelf: 'center',
      color: 'black'
   }
});

I want to use each selected item and loop through the API several times to get information on each picked item.

Answer 1

You can do it several ways. If you want to make an api call when user selects a new beer then the following code may be helpful:

add apiData: {} to initial state

add this.fetchBeerFromApi(itemValue); in the addBeer function

// notice I used es7 fat arrow functions to avoid having to bind in constructor
fetchBeerFromApi = async (beerId) => {
  let response = await fetch(`${BREWERY_API_URL}/beer/${beerId}`);
  response = await response.json();

  if (response.error) {
    console.error('Error with brewery api beer request', response.error);
    return false;
  }
  const apiData = this.state.apiData;
  apiData[beerId] = response;
  // Or handle storing apiData somewhere else... I usually use immutable data
  // structures to avoid deeply nested data not triggering re-rendering issues
  // so this may or may not be problematic...
  // Here is the immutablejs alternative to those last two lines:
  // const apiData = this.state.apiData.set(beerId, response);

  // Here we store it back to state where you can handle rendering the data if
  // it is available
  this.setState({apiData});
}