Unexpected token import in custom node environment

问题

I am getting a SyntaxError: Unexpected token import when using my custom class that extends NodeEnvironment. When not using a custom test environment, modern JavaScript - ES modules, etc. works fine.

I'm using node 8.11.1 and yarn 1.6.0.

This is the full error:

$ jest --no-cache
FAIL  __tests__/math.js
  ● Test suite failed to run

    /home/user/workspace/web/jest-custom-environment-no-import/__tests__/_helpers_/environments/integration.js:1
    (function (exports, require, module, __filename, __dirname) { import NodeEnvironment from 'jest-environment-node';
                                                                  ^^^^^^

    SyntaxError: Unexpected token import

      at node_modules/jest-runner/build/run_test.js:31:29

This is my .babelrc:

{
  "presets": [
    [
      "@babel/preset-env",
      {
        "targets": {
          "node": "current"
        },
        "shippedProposals": true
      }
    ]
  ]
}

And the jest portion of my package.json:

"jest": {
  "testEnvironment": "./__tests__/_helpers_/environments/integration.js",
  "testPathIgnorePatterns": ["/node_modules/", "/_helpers_/"],
  "verbose": true
}

The custom environment:

import NodeEnvironment from 'jest-environment-node';

export default class IntegrationEnvironment extends NodeEnvironment {
  async setup() {
    await super.setup();
  }

  async teardown() {
    await super.teardown();
  }

  runScript(script) {
    return super.runScript(script);
  }
}

I've also created a GitHub repo that demonstrates this issue.

回答1:

I created a sensible workaround using esm. I created an additional file that loads esm, which loads my custom Jest environment.

My package.json now contains:

"jest": {
  "testEnvironment": "./__tests__/_helpers_/environments/integration.index.js",
  "testPathIgnorePatterns": ["/node_modules/", "/_helpers_/"],
  "verbose": true
}

The file ./__tests__/_helpers_/environments/integration.index.js contains:

// eslint-disable-next-line no-global-assign
require = require('esm')(module);

module.exports = require('./integration').default;

./__tests__/_helpers_/environments/integration.js remains unchanged.

A working example is found in the esm branch of my original repo.

来源：https://stackoverflow.com/questions/49930302/unexpected-token-import-in-custom-node-environment

标签

jestjs