It seems that Jest cannot pick up imported library. I've been reading about it and trying various options. One of those was this. However none of them seems to work.
//xyz.ts
..
/* eslint-disable */
import * as csv from 'csv-stringify/sync';
/* eslint-enable */
..
After running Jest:
Test suite failed to run
Cannot find module 'csv-stringify/sync' from 'xyz.ts'
Library being used - https://csv.js.org/stringify/ .
I suspect I do something wrong, because even ESLint complains that about it, if I don't disable its checks.
Unable to resolve path to module 'csv-stringify/sync' import/no-unresolved
Library's structure:
Furthermore, if I'm trying to import as
import * as csv from 'csv-stringify/lib/sync';
Then I receive this error after running Jest
Test suite failed to run
Jest encountered an unexpected token
Jest failed to parse a file. This happens e.g. when your code or its dependencies use non-standard JavaScript syntax, or when Jest is not configured to support such syntax.
Out of the box Jest supports Babel, which will be used to transform your files into valid JS based on your Babel configuration.
By default "node_modules" folder is ignored by transformers.
Here's what you can do:
• If you are trying to use ECMAScript Modules, see https://jestjs.io/docs/ecmascript-modules for how to enable it.
• If you are trying to use TypeScript, see https://jestjs.io/docs/getting-started#using-typescript
• To have some of your "node_modules" files transformed, you can specify a custom "transformIgnorePatterns" in your config.
• If you need a custom transformation specify a "transform" option in your config.
• If you simply want to mock your non-JS modules (e.g. binary assets) you can stub them out with the "moduleNameMapper" config option.
You'll find more details and examples of these config options in the docs:
https://jestjs.io/docs/configuration
For information about custom transformations, see:
https://jestjs.io/docs/code-transformation
Details:
<redacted>/node_modules/csv-stringify/lib/sync.js:2
import { Stringifier } from './index.js';
^^^^^^
I guess some kind of transformation might be needed here?
Other files:
jest.config.js
module.exports = {
// Root path
roots: [''],
// testMatch: ['**/__tests__/**/*.+(ts|tsx|js)', '**/?(*.)+(spec|test).+(ts|tsx|js)'],
// Only test TS files, don't test JS
testMatch: ['**/?(*.)+(spec|test).+(ts)'],
transform: {
'^.+\\.(ts|tsx)$': 'ts-jest',
},
// Include below folders to be checked for modules
moduleDirectories: ['node_modules', 'src'],
};
tsconfig.json
{
"compilerOptions": {
"module": "commonjs",
"noImplicitReturns": true,
"noUnusedLocals": true,
"outDir": "lib",
"sourceMap": true,
"strict": true,
"target": "es2017",
"strictNullChecks": true
},
"compileOnSave": true,
"include": [
"coverage",
"jest.config.js",
"src",
"test"
]
}
Addressing suggestions below:
Import it from dist - lib is the source (untranspiled) file which is why you get the second error.
Tried cjs and esm - both didn't work
import * as csv from 'csv-stringify/dist/cjs/sync';
..
Error
Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './dist/cjs/sync' is not defined by "exports"
Have you tried import { stringify } from 'csv-stringify/sync'; as the library suggests?
Yes - I receive yet another error.
Error [ERR_PACKAGE_PATH_NOT_EXPORTED]: Package subpath './lib/sync' is not defined by "exports" in <redacted>/node_modules/csv-stringify/package.json
package.json exports part
"exports": {
".": {
"import": "./lib/index.js",
"require": "./dist/cjs/index.cjs"
},
"./sync": {
"import": "./lib/sync.js",
"require": "./dist/cjs/sync.cjs"
},
"./browser/esm/": "./dist/esm/"
}
