Blog>
Snippets

Optimizing Nested Data with useMemo

Explores a use case for useMemo to optimize chart performance when dealing with nested data structures, ensuring calculations are performed only when necessary.
import React, { useMemo } from 'react';
import { Chart } from 'chart.js';

const MyChartComponent = ({ data }) => {
  // This useMemo will recompute the transformedData only if 'data' changes
  const transformedData = useMemo(() => {
    // Assuming 'data' is an array of objects representing
    // the nested data structure
    return data.map(item => ({
      ...item,
      // Perform some transformation for the chart
      value: item.value * 2 // Example transformation
    }));
  }, [data]);

  useEffect(() => {
    const ctx = document.getElementById('myChart').getContext('2d');
    new Chart(ctx, {
      // Chart configuration here, using transformedData
      type: 'line', // Example chart type
      data: {
        datasets: [{
          data: transformedData // Use the memoized data
        }]
      }
    });
  }, [transformedData]);

  return <canvas id="myChart"></canvas>;
};
This code snippet demonstrates how to use useMemo to optimize the performance of a React component that renders a chart using Chart.js. The useMemo hook is used to memoize the transformed data structure needed for the chart, ensuring that this potentially expensive computation is only redone when the input data changes.