I don't want to need to use .babelrc file in all cases (build script) but can't seem to find a syntax to pass nested options to the CLI. Here is a simplified version of my .babelrc that I need to pass on the command line:
{"presets": [ ["es2015", { "modules": false }] ], "compact": true }
Anyone know the syntax for this?
Babel does not currently support passing options to presets or plugins via the CLI.
Related
I'm a bit new to babel, but what I'm trying to do is set it to run only when running npm run test and in no other contexts.
I thought that if I configure .babelrc like below, it will only take effect when I use "scripts"."test": "NODE_ENV=test ./node_modules/.bin/jest --no-cache" in package.json, but babel somehow applies (and messes up things) even with npm run watch, which uses NODE_ENV=development.
{
"env": {
"test": {
"presets":[
["#babel/preset-env"],"#babel/react"
],
"plugins": [
"transform-es2015-modules-commonjs",
"dynamic-import-node"
]
}
}
}
I get a TypeError: this.setDynamic is not a function. I have to remove entire babel dependencies and configurations for project to work again, but then I can't run the jest tests.
I have a requirement where I am trying to use the Babel plugin "preset-env". This plugin compiles my NextJS project from ES6 to ES5. I have created the .babelrlc file as suggested by NextJS documentation and added my plugin like this:
{
"presets": ["next/babel"],
"plugins": ["#babel/preset-env"]
}
When I try to run my project locally I get this error:
error - ./node_modules/next/dist/client/router.js
Error: Cannot find module '#babel/plugin-preset-env' from '/Users/agastya/Local/testcap/Sample-proj'
- If you want to resolve "#babel/preset-env", use "module:#babel/preset-env"
- Did you accidentally pass a preset as a plugin?
NextJS documentation says "Next.js includes the next/babel preset to your app, which includes everything needed to compile React applications and server-side code. ".
It would be great if someone can explain where/what is the right approach to fix this.
You have to do the following:
// .babelrc file, also could be babel.config.js
{
"presets": [
[
"next/babel",
{
"preset-env": {},
"transform-runtime": {},
"styled-jsx": {},
"class-properties": {}
}
]
],
"plugins": []
}
Taken from: https://nextjs.org/docs/advanced-features/customizing-babel-config
I'm using styled components (via Emotion) and I've found vscode-styled-components plugin to provide appropriate syntax highlighting in vscode. It works very well.
Out of the box, it requires one of 4 tags to be used with the a template literal to recognize the block as a css-string: "styled", "css", "injectGlobal" or "createGlobalStyle".
I would like to use my own custom tag rather than any of these 4.
The plugin doc points to its dependency for configuration info: typescript-styled-components. It shows how to configure the use of additional tags via typescrips's compilerOptions. My react project is not built with typescript, so this is not an option for me.
Question: is there any way to configure the use of tags in a non-typescript project?
Just use a jsconfig.json file instead of tsconfig.json. At the root of your project, create a jsconfig.json file with the contents:
{
"compilerOptions": {
"target": "es6",
"plugins": [
{
"name": "typescript-styled-plugin",
"tags": [
"styled",
"css",
"sty"
]
}
]
},
"exclude": [
"node_modules",
"**/node_modules/*"
]
}
jsconfigs define settings for javascript projects
Also note that the tag options currently do not effect syntax highlighting, only intellisense
I seem to absolutely not grasp where to put root programmatic options for the babel.
If I have a monorepo and need to tell the different sub packages that they shall look upwards for my babel.config.js then I should put rootMode: "upwards" into the .babelrc of the sub packages, correct? This does not work, because of the resulting error
Error: .rootMode is only allowed in root programmatic options
Somehow I simply can't find any example of where to put/use root programmatic options... Can anyone point me to the right direction?
If you are using Webpack, you need to put it there.
module: {
[..]
rules: [
// Transpile ES6 Javascript into ES5 with babel loader
{
test: /\.jsx?$/,
exclude: [/node_modules/, /json/],
loader: 'babel-loader',
options: {
rootMode: 'upward'
},
},
[..]
],
[..]
},
Otherwise I had the same issue than you, I can't put it in the package.json file using the key babel.
Any API-related options are called programmatic options. Take a look at my discussion with the primary maintainer of Babel: https://github.com/babel/babel/discussions/14405.
It's when you specify them directly to Babel (babel.transformSync(code, programmaticOptions) or to the Babel integration you are using (e.g. babel-loader, which can pass them to its internal babel.transform call). In other words, not in presets or config files. [...]
by #nicolo-ribaudo - Babel core team.
I got this error using my (probably non-standard) monorepo setup where I have top-level subdirectories for each of my packages. No top-level package. When I upgraded to Babel 7, my Jest tests were no longer transforming packages that were yarn linked into the package where I was running Jest.
I added a top-level babel.config.js as part of Babel's monorepo instructions. I had rootMode: "upwards" in these three places:
ui-package/webpack.config.js for transforming the app.
ui-package/babel-jest.js for the tests, where it appeared like:
module.exports = require("babel-jest").createTransformer({
rootMode: "upward",
})
and was referenced from jest.config.js in that same dir like:
transform: {
"^.+\\.jsx?$": "./babel-jest.js",
},
And in /babel.config.js, the newly added top-level babel conf file.
Removing it from the last one removed the error.
I am trying to set up Jest on a React based project which uses ES6 modules. However I seem to be having issues with ES6 modules, I am using babel-jest and believe I have this set up properly (Jest detects it automatically).
Jest doesn't seem to have a problem using ES6 imports however as soon as it hits on an import statement within one of the imported modules it chokes. It's as if it is only transpiling the initial test script and not any of the imported modules. I have tried various configurations and tried searching Google with no luck. Running tests without any imports works fine.
Here is the error:
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import Predications from './predications';
^^^^^^
SyntaxError: Unexpected token import
Here are the relevant bits of config:
jest.conf.json
{
"testRegex": "\/test\/spec\/.*\\.js$",
}
.babelrc
{
"presets": ["es2015", "stage-0", "react"]
}
Test script
import React from 'react';
import { mount, shallow } from 'enzyme';
import Slider from 'react-slick';
import Carousel from '../../client/components/carousel/carousel.js'; // test chokes on when I include this module
describe('carousel component', () => {
it('is a test test case', () => {
expect(1 + 2).toEqual(3);
});
});
Update:
As suggested, I have tried running the test without jest.conf.js, however the testRegex is needed in order for Jest to find my tests, I tried moving tests to the default test directory and they still fail.
I would like to clarify that tests themselves are running fine, the issue seems to be where one of my imported modules uses ES6, in my example above, if I don't import my carousel component the test runs fine, as soon as I import that the test chokes on the import statement within that file. It seems as though the imported modules are not getting transpiled.
Update #2
After some investigation it appears the issue is that babel is not transpiling ES6 within node_modules. I have created an example repo to demonstrate this here: https://github.com/jamiedust/babel-jest-example
I understand that third party modules should be handling their own transpiling, however we have a number of modules which are hosted on our own npm registry and are re-used between projects, in these cases Webpack handles transpiling, for the Jest tests we need these node_modules to be transpiled by Babel, or a way of leveraging our webpack set up to do this for us.
Solution
Add the following config in package.json (or Jest config file).
"jest": {
"transformIgnorePatterns": [
"/node_modules/(?!test-component).+\\.js$"
]
}
By default any code in node_modules is ignored by babel-jest, see the Jest config option transformIgnorePatterns. I've also created a PR on your example repo, so you can see it working.
While this works, I've found it to be extremely slow in real applications that have a lot of dependencies containing ES modules. The Jest codebase has a slightly different approach to this as you can find in babel-jest transforming dependencies. This can also take much longer on Windows, see Taking 10 seconds on an empty repo.
If doing "unit" testing, mocking is probably the better way to go.
You could try adding the transform-es2015-modules-commonjs plugin to your babel config file for testing only. Here is an example config file which tells babel to transpile modules only when in a testing environment. You can put it underneath your presets:
{
"presets": [
"react",
["es2015", {"modules": false, "loose": true}]
],
"env": {
"test": {
"plugins": ["transform-es2015-modules-commonjs"]
}
}
}
You can read about the plugin here:
https://www.npmjs.com/package/babel-plugin-transform-es2015-modules-commonjs
Then, when running your Jest tests on the command line specify NODE_ENV=test (you may need to add the --no-cache flag to the command the first time after making the change to the babel config because Jest caches babel output, but after that you can leave it off:
NODE_ENV=test jest --no-cache
I learned about this issue in a React seminar by Brian Holt at Frontend Masters. https://frontendmasters.com/courses/
faced the same issue, followed the steps to resolve,
install babel-jest
in jest config add this configuration
transform: {
'^.+\\.js?$': require.resolve('babel-jest')
}
make sure you have babel.config.js present (your config might be different than provided below)
module.exports = {
"env": {
"test": {
presets: [
[
'#babel/preset-env',
{
targets: {
node: 'current',
},
},
],
]
}
}
};
I faced the same problem (node_module not transpiled by babel-jest), without being able to solve it.
Instead, I finally succeed by mocking the node_module, like described here https://facebook.github.io/jest/docs/manual-mocks.html
NB: setting mocks in __mocks__ subfolders did not work for me. So I passed the mock as the second parameter of the jest.mock() function. Something like :
jest.mock('your_node_module', () => {})
Another possible cause. Babel now ignores your .babelrc inside node_modules and uses the one provided by the dependency. If you have control of the dependency you would have to add a .babelrc to it and babel would use those settings for it.
this can cause problems though if your dependency and your project use different babel versions or modules.