For some reason, my jest configuration doesn't work with the latest version of d3-path@3.0.1. It worked fine with version 2.0.0. I guess it has something to do with d3-path switching to ESM, but I was already using ES6 in my own code, so I don't get why it suddenly doesn't work anymore. I have the following packages installed:
"dependencies": {
"d3-path": "^3.0.1"
},
"devDependencies": {
"@babel/core": "^7.15.8",
"@babel/preset-env": "^7.15.8",
"babel-jest": "^27.3.1",
"jest": "^27.3.1"
}
My babel.config.js:
module.exports = {
presets: [['@babel/preset-env', {targets: {node: 'current'}}]],
};
My index.js:
import { path } from 'd3-path'
export default () => path()
The test file:
import fn from '../src/index.js'
describe('test', () => {
it('works', () => {
fn()
expect(2 + 2).toBe(4)
})
})
The error message:
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){export {default as path} from "./path.js";
^^^^^^
SyntaxError: Unexpected token 'export'
> 1 | import { path } from 'd3-path'
To reproduce:
git clone https://github.com/luucvanderzee/jest-problem.git
cd jest-problem
npm i
npm run test
// The test runs without failure- this is because we're currently still using d3-path@2.0.0
npm uninstall d3-path && npm install d3-path // (upgrade to d3-path@3.0.1)
npm run test
// Now the test fails.
How should I configure jest and/or babel to solve this issue?
EDIT:
I already tried the following (from this page of the jest docs):
- Creating a
jest.config.jsfile with the following:
module.exports = {
transform: {}
}
- Changing my
"test"command from"jest"to"node --experimental-vm-modules node_modules/jest/bin/jest.js"
This gives me another error:
/home/luuc/Projects/javascript/jest-problem/test/test.test.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){import fn from '../src/index.js'
^^^^^^
SyntaxError: Cannot use import statement outside a module
I also don't get what is meant by
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
Isn't the problem that the module is not transformed? Would adding an ignore pattern not just lead to the module not getting transformed?