Next.js: window is not defined

Question

I'm trying to use apexcharts for a next.js application and it's returning me window is not defined.

I would love any help with that.

Does someone know what is happening and why?

import React from 'react';
import Chart from 'react-apexcharts';

export default class Graficos extends React.Component <{}, { options: any, series: any }> {
    constructor(props:any) {
        super(props);

        this.state = {
            options: {
            chart: {
                id: "basic-bar"
            },
            xaxis: {
                categories: [1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999]
            }
            },
            series: [
            {
                name: "series-1",
                data: [30, 40, 45, 50, 49, 60, 70, 91]
            }
            ]
        };
    }
  
    render() {
        return (
            <div className="row">
                <h1>Gráfico Básico</h1>
                <div className="mixed-chart">
                    <Chart
                        options={this.state.options}
                        series={this.state.series}
                        type="bar"
                        width={500}
                    />
                </div>
            </div>
        );
    }
  }

Answer 1

One of Next.js's key features is that it can render parts of your React application on the server or even at build time. While this can be helpful in improving your page's performance, the downside is that the server does not provide the all same APIs that your application would have access to in the browser. In this case, there is no global window object defined.

Unfortunately, searching the source code for apexcharts.js turns up many references to window: https://github.com/apexcharts/apexcharts.js/search?q=window. This also occurs in their React wrapper: https://github.com/apexcharts/react-apexcharts/blob/ecf67949df058e15db2bf244e8aa30d78fc8ee47/src/react-apexcharts.jsx#L5. While there doesn't seem to be a way to get apexcharts to avoid references to window, you can prevent Next.js from using the chart on the server. The simplest way to do that is to wrap any reference to the code with a check for whether window is defined, e.g.

<div className="mixed-chart">
  {(typeof window !== 'undefined') &&
  <Chart
    options={this.state.options}
    series={this.state.series}
    type="bar"
    width={500}
  />
  }
</div>  

With apexcharts, you will also need to do this for the component import because the import alone will trigger a reference to window as shown in that second link. In order to get around that problem you will need to use a dynamic import as opposed to the normal import you currently have: https://nextjs.org/docs/advanced-features/dynamic-import

import dynamic from 'next/dynamic'

const Chart = dynamic(() => import('react-apexcharts'), { ssr: false });