title: React Native adding to an array of states
body: <p>I am trying to add an array of to my state of beer. What I am looking to accomplish is based on the users choice of favorite beers it adds those specific values on to the state.</p>
  
  <p>the error I am receiving is that 'undefined is not a function' that points to my function to add the state. </p>
  
  <pre><code>import React, { Component } from 'react';
  import { View, Text, Picker, StyleSheet } from 'react-native'
  
  class BeerPicker extends Component {
    constructor(props){
        super(props);
        this.state = {
            beer: []
        };
    }
    addBeer(newbeer){  &lt;== function throws error
        this.setState((state) =&gt; {
            beer: state.addBeer.push(newbeer)
        });
    }
     render() {
        return (
           &lt;View&gt;
              &lt;Picker selectedValue = {this.state.beer} onValueChange = {this.addBeer}&gt;
                 &lt;Picker.Item label = "IPA" value = "ipa" /&gt;
                 &lt;Picker.Item label = "Pilsner" value = "pilsner" /&gt;
                 &lt;Picker.Item label = "Stout" value = "stout" /&gt;
              &lt;/Picker&gt;
              &lt;Text style = {styles.text}&gt;{this.state.beer}&lt;/Text&gt;
           &lt;/View&gt;
        )
     }
  }
  export default BeerPicker;
  
  const styles = StyleSheet.create({
     text: {
        fontSize: 30,
        alignSelf: 'center',
        color: 'red'
     }
  })
  </code></pre>
  
  <p>Fairly new to React Native so any input would be much accomplished!</p>