Hicharts Export Server - ERR_REQUIRE_ESM

Question

Created my own custom export server from here: https://github.com/highcharts/node-export-server, at the time time of writting v 4.0.2. Installed puppeteer, chrome, a bunch of required libraries, pm2 and node v20.15.1.

After this, while using the CLI, enabled the export server with the command highcharts-export-server --enableServer 1 --port 8000 --noDownload 0 and everything works as expected.

As per the documentation from the above, I'm trying to keep the process alive using pm2. After running this command: pm2 start highcharts-export-server -- --enableServer 1 --port 8000 --noDownload 0 the process starts and when I check it with pm2 list it has the status errored.

The error below:

Error [ERR_REQUIRE_ESM]: require() of ES Module /var/www/.nvm/versions/node/v20.15.1/lib/node_modules/highcharts-export-server/bin/cli.js not supported.

Instead change the require of cli.js in null to a dynamic import() which is available in all CommonJS modules. at Object. (/var/www/.nvm/versions/node/v20.15.1/lib/node_modules/pm2/lib/ProcessContainerFork.js:33:23) { code: 'ERR_REQUIRE_ESM' }

From googling I've found out that certain libraries are only compatible with ESM modules and thus wants you to load it with import and not require(), searched the code and couldn't find any instance of require()

I am not sure how to proceed further

Answer 1

There is no require() in the highcharts-export-server code there, but pm2 uses require() when you start the highcharts-export-server without specifying how to handle ES modules; pm2 tries to load the script using require() which leads to this error.

You could try out one of the following solutions:

1. Try to run pm2 with an additional node flag: pm2 start "highcharts-export-server/bin/cli.js" --node-args="--experimental-modules" -- --enableServer 1 --port 8000 --noDownload 0

2. Rename the file to .mjs: pm2 start cli.mjs -- --enableServer 1 --port 8000 --noDownload 0

3. Use Export Server (/dist) as a node module in your application (either CommonJS or ESM, the /dist directory is built by Rollup with the npm run build command but it's also available on GH):

// Import the Highcharts Export Server module
const exporter = require('highcharts-export-server');

// Export options correspond to the available CLI/HTTP arguments described above
const options = {
  export: {
    type: 'png',
    options: {
      title: {
        text: 'My Chart'
      },
      xAxis: {
        categories: ["Jan", "Feb", "Mar", "Apr"]
      },
      series: [
        {
          type: 'line',
          data: [1, 3, 2, 4]
        },
        {
          type: 'line',
          data: [5, 3, 4, 2]
        }
      ]
    }
  }
};

// Initialize export settings with your chart's config
const exportSettings = exporter.setOptions(options);

// Must initialize exporting before being able to export charts
await exporter.initExport(exportSettings);

// Perform an export
await exporter.startExport(exportSettings, async (error, info) => {
  // The export result is now in info
  // It will be base64 encoded (info.data)

  // Kill the pool when we are done with it
  await exporter.killPool();
});