Maximum update depth exceeded when using useEffect with state updates

I'm facing a "Maximum update depth exceeded" error in my React Native application. The issue occurs when I uncomment the DropDownPicker component in my CropsGraph component. Here's the flow of my application:

I fetch graphData in DataAnalysis.js and pass it as a prop to CropsGraph.js.

In CropsGraph.js, I process the graphData to generate data for graphs and pass it to ChartScreen.js.

I use useEffect in CropsGraph.js to process the data whenever graphData or selectedCrop changes.

Here's the relevant code for CropsGraph.js:

import React, { useEffect, useState, useCallback } from 'react';
import { ScrollView, StyleSheet, Text, View } from 'react-native';
import ChartScreen from './ChartScreen';
import DropDownPicker from 'react-native-dropdown-picker';
import { transformData, processBarData } from '../../../config/HelperFunction/index';

export const CropsGraph = ({ graphData }) => {
  const [graphState, setGraphState] = useState({
    data: null,
    years: [],
    feedback: '',
    graphs: [],
  });
  const [cropOpen, setCropOpen] = useState(false);
  const [selectedCrop, setSelectedCrop] = useState(3);
  const colors = ['#FFA500', '#2e8b57', '#9F2B68'];

  const processGraphData = useCallback((key, firstYearData, secondYearData, thirdYearData) => {
    const keyUnits = {
      COST: '(RS.)',
      CULTIVATED_AREA: '(ACRE)',
      YIELD: '(MOUND/ACRE)',
      TOTAL_PRODUCTION: '(MOUND)',
      CASHFLOW: '(RS.)',
      RATE: '(RS.)',
    };
    const result = processBarData(key, firstYearData, secondYearData, thirdYearData, colors);
    const unit = keyUnits[key] || '';
    return {
      data: result.data,
      max: result.maxValue,
      sections: result.numberOfSections,
      title: `${key.replace(/_/g, ' ')} ${unit}`,
    };
  }, []);

  const updateGraphState = useCallback(() => {
    if (graphData && Object.keys(graphData).length > 0) {
      const keys = Object.keys(graphData);
      const years = keys;

      let firstYearData = graphData[keys[0]]?.[selectedCrop]
        ? transformData(graphData[keys[0]][selectedCrop])
        : null;

      let secondYearData = graphData[keys[1]]?.[selectedCrop]
        ? transformData(graphData[keys[1]][selectedCrop])
        : null;

      let thirdYearData = graphData[keys[2]]?.[selectedCrop]
        ? transformData(graphData[keys[2]][selectedCrop])
        : null;

      const feedback =
        thirdYearData?.FEEDBACK || secondYearData?.FEEDBACK || firstYearData?.FEEDBACK || '';

      const graphKeys = [
        'COST',
        'CULTIVATED_AREA',
        'RATE',
        'YIELD',
        'TOTAL_PRODUCTION',
        'CASHFLOW',
      ];

      const graphs = graphKeys.map((key) =>
        processGraphData(key, firstYearData, secondYearData, thirdYearData)
      );

      setGraphState({ data: graphData, years, feedback, graphs });
    } else {
      setGraphState({ data: null, years: [], feedback: '', graphs: [] });
    }
  }, [graphData, selectedCrop, processGraphData]);

  useEffect(() => {
    updateGraphState();
  }, [graphData, selectedCrop, updateGraphState]);

  return (
    <View style={styles.safeAreaStyle}>
      <ScrollView>
        <DropDownPicker
          placeholder="Select Crop"
          open={cropOpen}
          value={selectedCrop}
          setOpen={setCropOpen}
          setValue={setSelectedCrop}
        />
        {graphState.graphs.map((graph, index) =>
          graph.data.length > 0 ? (
            <View key={index} style={styles.chartContainer}>
              <Text style={styles.chartTitle}>{graph.title}</Text>
              <ChartScreen
                barData={graph.data}
                numberOfSections={graph.sections}
                max={graph.max}
                years={graphState.years}
                feedback={graphState.feedback}
              />
            </View>
          ) : (
            <View key={index} style={styles.emptyContainer}>
              <Text>No Data Available for {graph.title}</Text>
            </View>
          )
        )}
      </ScrollView>
    </View>
  );
};

const styles = StyleSheet.create({
  safeAreaStyle: { flex: 1, backgroundColor: 'white' },
  chartContainer: { marginVertical: 15 },
  chartTitle: { fontSize: 18, fontWeight: 'bold', marginBottom: 5, textAlign: 'center' },
  emptyContainer: { flex: 1, justifyContent: 'center', alignItems: 'center', padding: 16 },
});

If I comment out the DropDownPicker, the component works fine without any errors.

When I uncomment DropDownPicker, I get the "Maximum update depth exceeded" error.

Console shows the useEffect runs repeatedly even though dependencies like graphData and selectedCrop are stable.

How can I fix the infinite loop issue caused by DropDownPicker and ensure my useEffect only runs when necessary? Is there a better way to handle this kind of state-dependent data processing in React Native?

Get rid of your useEffect altogether. GraphData shouldn’t be a new state value, it should be a memoized derived value from the props. Try this out:

import React, { useEffect, useState, useCallback, useMemo } from "react";
import { ScrollView, StyleSheet, Text, View } from "react-native";
import ChartScreen from "./ChartScreen";
import DropDownPicker from "react-native-dropdown-picker";
import {
  transformData,
  processBarData,
} from "../../../config/HelperFunction/index";

const colors = ["#FFA500", "#2e8b57", "#9F2B68"];
const graphKeys = [
  "COST",
  "CULTIVATED_AREA",
  "RATE",
  "YIELD",
  "TOTAL_PRODUCTION",
  "CASHFLOW",
];
const keyUnits = {
  COST: "(RS.)",
  CULTIVATED_AREA: "(ACRE)",
  YIELD: "(MOUND/ACRE)",
  TOTAL_PRODUCTION: "(MOUND)",
  CASHFLOW: "(RS.)",
  RATE: "(RS.)",
};

export const CropsGraph = ({ graphData }) => {
  const [cropOpen, setCropOpen] = useState(false);
  const [selectedCrop, setSelectedCrop] = useState(3);

  const processedData = useMemo(() => {
    if (!graphData || Object.keys(graphData).length < 1) {
      return { data: null, years: [], feedback: "", graphs: [] };
    }
    const keys = Object.keys(graphData);
    const years = keys;

    let firstYearData = graphData[keys[0]]?.[selectedCrop]
      ? transformData(graphData[keys[0]][selectedCrop])
      : null;

    let secondYearData = graphData[keys[1]]?.[selectedCrop]
      ? transformData(graphData[keys[1]][selectedCrop])
      : null;

    let thirdYearData = graphData[keys[2]]?.[selectedCrop]
      ? transformData(graphData[keys[2]][selectedCrop])
      : null;

    const feedback =
      thirdYearData?.FEEDBACK ||
      secondYearData?.FEEDBACK ||
      firstYearData?.FEEDBACK ||
      "";

    const graphs = graphKeys.map((key) => {
      const result = processBarData(
        key,
        firstYearData,
        secondYearData,
        thirdYearData,
        colors
      );
      const unit = keyUnits[key] || "";
      return {
        data: result.data,
        max: result.maxValue,
        sections: result.numberOfSections,
        title: `${key.replace(/_/g, " ")} ${unit}`,
      };
    });

    return { data: graphData, years, feedback, graphs };
  }, [graphData, selectedCrop]);

  return (
    <View style={styles.safeAreaStyle}>
      <ScrollView>
        <DropDownPicker
          placeholder="Select Crop"
          open={cropOpen}
          value={selectedCrop}
          setOpen={setCropOpen}
          setValue={setSelectedCrop}
        />
        {processedData.graphs.map((graph, index) =>
          graph.data.length > 0 ? (
            <View key={index} style={styles.chartContainer}>
              <Text style={styles.chartTitle}>{graph.title}</Text>
              <ChartScreen
                barData={graph.data}
                numberOfSections={graph.sections}
                max={graph.max}
                years={processedData.years}
                feedback={processedData.feedback}
              />
            </View>
          ) : (
            <View key={index} style={styles.emptyContainer}>
              <Text>No Data Available for {graph.title}</Text>
            </View>
          )
        )}
      </ScrollView>
    </View>
  );
};

const styles = StyleSheet.create({
  safeAreaStyle: { flex: 1, backgroundColor: "white" },
  chartContainer: { marginVertical: 15 },
  chartTitle: {
    fontSize: 18,
    fontWeight: "bold",
    marginBottom: 5,
    textAlign: "center",
  },
  emptyContainer: {
    flex: 1,
    justifyContent: "center",
    alignItems: "center",
    padding: 16,
  },
});