React Native : How to retrieve data from a State with a nested json array and Map that state to get a particular value with a given id

Question

I have a react native picker which has an array of objects that i have fetched from my API and saved to state under properties. This is a screenshot of my data fetched

I need to find the correct object in the array from the _id when I select the Property dropdown. I need this do be done using Javascript logic without making a second call to my server. This is my code inside the render for drop down

 <View style={{margin: 20, flexDirection: 'row', flex: 1}}>
                        {/*PROPERTY....................................................*/}
                        <View style={{padding: '10px'}}>
                            <Picker style={styles.picker} selectedValue={this.state.pickerProperty}
                                    onValueChange={(itemValue, itemIndex) => this.getPropertyById(itemValue)}>
                                <Picker.Item label="Select Property" value=""/>
                                {this.state.properties.map((item, key) => (
                                    <Picker.Item label={item.PropertyName} value={item._id} key={key}/>
                                ))}
                            </Picker>
                            {/*{this.getPropertyById()}*/}
                        </View>
                        {/*TYPE........................................................*/}
                        <View style={{padding: 10}}>
                            <Picker style={styles.picker} selectedValue={this.state.pickerType}
                                    onValueChange={(itemValue, itemIndex) => this.setState({pickerType: itemValue})}>
                                <Picker.Item label="Select Type" value=""/>
                                {this.state.propById.map((item, key) => (
                                    <Picker.Item label={item.tname} value={item.tname} key={key}/>
                                ))}

                            </Picker>
                            <Text>{this.state.pickerType}</Text>
                        </View>
                    </View>

I need to write my code inside this function

 getPropertyById=(itemValue)=> { //Need the code here
}

Answer 1

Found this solution and it helped me.

    changeProperty(event) {
    this.setState({selectedProperty: event.target.value});
    this.setState({types: this.state.properties.find(property => property.PropertyName === event.target.value).Type})

}

changeType(event) {
    this.setState({selectedType: event.target.value});
    const Ty = this.state.properties.find(property => property.PropertyName === this.state.selectedProperty).Type;
    this.setState({items: Ty.find(Typ => Typ.typename === event.target.value).Item})

}

Using each of these in onChange={} of each dropdown will solve the problem. Do not forget to modify your constructor as follows

   constructor(props) {
    super(props);
    this.changeProperty = this.changeProperty.bind(this);
    this.changeType = this.changeType.bind(this);

}