`ReferenceError: TextEncoder is not defined` when running `react-scripts test --env=jsdom`

I'm using a TensorFlow encoder in my application. It works fine in my browser when the application is running but I get issues when testing that it builds:

$ npx react-scripts test --env=jsdom
FAIL  src/App.test.js
  ● Test suite failed to run

    ReferenceError: TextEncoder is not defined

      16 | import TextField from '@material-ui/core/TextField';
      17 | import Typography from '@material-ui/core/Typography';
    > 18 | import * as mobilenet from '@tensorflow-models/mobilenet';
         | ^
      19 | import * as UniversalSentenceEncoder from '@tensorflow-models/universal-sentence-encoder';
      20 | import * as tf from '@tensorflow/tfjs';
      21 | import axios from 'axios';

      at new PlatformBrowser (node_modules/@tensorflow/tfjs-core/src/platforms/platform_browser.ts:26:28)
      at Object.<anonymous> (node_modules/@tensorflow/tfjs-core/src/platforms/platform_browser.ts:50:30)
      at Object.<anonymous> (node_modules/@tensorflow/tfjs-core/src/index.ts:29:1)
      at Object.<anonymous> (node_modules/@tensorflow/tfjs-converter/src/executor/graph_model.ts:18:1)
      at Object.<anonymous> (node_modules/@tensorflow/tfjs-converter/src/index.ts:17:1)
      at Object.<anonymous> (node_modules/@tensorflow-models/mobilenet/dist/index.js:38:14)
      at Object.<anonymous> (src/components/model.js:18:1)
      at Object.<anonymous> (src/App.js:8:1)
      at Object.<anonymous> (src/App.test.js:3:1)

I'd like to get rid of that error. I've tried using the 'text-encoding' package but I'm not sure how get TextEncoder properly defined before the import happens.

Maybe I can set a different option for --env?

I get the same error without --env=jsdom. I believe I added it after getting similar types of not defined errors and it corrected an issue.

Here is my test:

import React from 'react';
import ReactDOM from 'react-dom';
import App from './App';

it('renders without crashing', () => {
  const div = document.createElement('div');
  ReactDOM.render(<App />, div);
  ReactDOM.unmountComponentAtNode(div);
});

So setting --env=node does not work either because: ReferenceError: document is not defined.

Solution

jsdom Doesn't seem to have TextEncoder defined in global for the DOM. So you can fill it in with the node.js one.

test/custom-test-env.js:

const Environment = require('jest-environment-jsdom');

/**
 * A custom environment to set the TextEncoder that is required by TensorFlow.js.
 */
module.exports = class CustomTestEnvironment extends Environment {
    async setup() {
        await super.setup();
        if (typeof this.global.TextEncoder === 'undefined') {
            const { TextEncoder } = require('util');
            this.global.TextEncoder = TextEncoder;
        }
    }
}

npx react-scripts test --env=./test/custom-test-env.js