Have got a successful jest/esm setup, however occasionally a module is released that specifies both a main key (for commonjs) and a module key (for ESM) in its package.json. This leads to jest errors, for example with the uuid module:
/repo/path/node_modules/uuid/dist/esm-browser/index.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,jest){export { default as v1 } from './v1.js';
^^^^^^
SyntaxError: Unexpected token 'export'
I can see that dist/esm-browser/index.js is the file specified by the module key in package.json.
How can Jest w/ESM be configured to handle these cases, where stuff in node_modules is ESM?
Jest config:
{
"resetMocks": true,
"testEnvironment": "jsdom",
"testMatch": [
"**/src/**/*.(spec|test).[tj]s?(x)"
],
"preset": "ts-jest/presets/default-esm",
"extensionsToTreatAsEsm": [
".ts",
".tsx"
],
"globals": {
"ts-jest": {
"useESM": true
}
},
"globalSetup": "<rootDir>/jest/setup.cjs",
"globalTeardown": "<rootDir>/jest/teardown.cjs",
"watchPathIgnorePatterns": [
"<rootDir>/.tmp"
],
"moduleNameMapper": {
"^~/(.*)$": "<rootDir>/src/$1",
"^~components/(.*)$": "<rootDir>/src/components/$1",
"^~util/(.*)$": "<rootDir>/src/util/$1",
"^~types/(.*)$": "<rootDir>/src/types/$1"
}
}
I've had the same problem and it was fixed the same way as mentioned in this comment: https://github.com/nrwl/nx/issues/812#issuecomment-429420861 in my jest.config.js:
// list to add ESM to ignore
const esModules = ['uuid'].join('|');
// ...
module.exports = {
//...
transformIgnorePatterns: [`/node_modules/(?!${esModules})`],
// ...
};