I have a UI framework that is maintained by my company. and This library doesn't provide cjm module. instead only provide esm module.
And I aware that this library is not failed to be imported from the test condition running by jest.
through some gogooling, I found that the Jest doesn't support ESM module import, and it is only on experimental stage to support esm module on Jest(https://jestjs.io/docs/ecmascript-modules). So I tried to make my library as cjs module version, and test againg. This is perfectly works. So I convinced that the previous bug was caused because Jest doesn't support esm module import.
But at this point, I wonder something below.
If Jest don't support ESM, every library should have cjs module regardless of providing esm module??
Jest always find only cjs module from libraries?
How React test works on jest? even thought every react component and other modules are ESM? This is why we need react-test-renderer or babel-jest as dependencies for the react test?
Finally, There is some resources that I can find some information about this subject??
Related
Currently, i'm trying to run my svelte-kit application app to cpanel, but I wasn't able to because it uses ESM, and not commonjs. I've already tried to set type to module in my package.json, to no avail. My node.js version is 14, and I've done some research and it seems to me there is no way to compile a svelte-kit application to commonjs.
I would love if someone could show me a way to compile svelte-kit applications to commonjs, or use ESM modules on cpanel.
I am new to npmjs package publishing and recently published my 1st package successfully. But since it's written in ES5 style. It is accessed only via "require"
const smiley = require('smiley-id');
What should be done to make it accessible via import statement also? like this
import smiley from 'smiley-id';
or/and
import { smileyId } from 'smiley-id';
require is part of the CommonJS module system (also known as cjs modules) whereas import and export are used in es2015 module system (also known as JavaScript modules, es6 modules or esm modules).
You can use import for both cjs and esm modules, but you cannot use require for esm modules. This means that in an esm module (or source file which you will compile with Typescript tsc or Babel or bundle with Webpack) you can already import your package, as it is, with import. However, you cannot use named imports. Instead you have to destructure the imported item afterwards.
If you want to distribute it as an esm package, this is also possible and it comes with some advantages, out of which the most important is related to tree-shaking. To distribute it as an esm module, you tell your build tool to output esm modules. This is different for different tools. Fortsc for example you specify --module es6 (there are multiple targets that output esm modules). For Webpack, Babel and Rollup, the procedure is different.
I have a node dependency that is included in version 2 with require. Now with version 3 the library can only be included with import.
Error [ERR_REQUIRE_ESM]: require() of ES Module
But my script uses require.
Is there a way to include an ESM only package via require?
You can use dynamic import for this purpose but it's better to use the version that supports CommonJs unless you are using ESM itself
const thePackage = import('the-package');
Yes; I've built the fix-esm library for this purpose. It works basically by transparently converting ESM exports to CJS exports.
When I mock a core module in Jest, like jest.mock('fs'), and I create a file called __mocks__/fs.js, then I am using a mocked version of the module.
However, if any of the dependencies in the modules I'm testing also use fs, then they use the mocked version, which breaks them.
Is there a way to unmock these core modules, when they are used by deps, but otherwise not in my own modules?
Or is there an alternative way to achieve this?
Here an example is given how to import certain classes from a module:
import {ModalContainer, ModalDialog} from 'react-modal-dialog';
However, PhpStorm (latest EAP) gives me an error:
I installed the package with npm install react-modal-dialog and it is present in node_modules.
The equivalent var {ModalContainer, ModalDialog} = require('react-modal-dialog'); works fine.
I encountered this when setting up a React project and all i did was download the import's typescript definition, in my case just searched for react.
Instructions for adding libraries to your project can be found on webstorm's help page.
I think it caused by PHPStorm. The IDE can't understand the import syntax when import a CommonJS module.
I got this warning when using WebStorm 2016.1.2, too.
Taking react and react-router as example:
react is a CommonJS module, developed with ES5 syntax;
react-router is developed with ES2015 syntax, and compiled by Babel.
WebStorm 2016.1.2 can resolve Link exported by react-router module, but can't resolve createClass exported by react module.
Update:
browser-sync is a CommonJS module developed with ES5, too. But it works well on WebStorm, WebStorm can resolve all API exported by browser-sync.
It baffled me that WebStorm can't resolve react exported API.