I'm converting a project that was built using Create React App to use ParcelJS as a bundler instead. Strangely, a dependency that I imported during development (#twilio/voice-sdk) works fine in the CRA version of the application, but I get the following error when I try to invoke the constructor in the Parcel version:
TypeError: (this._options.AudioHelper || audiohelper_1.default) is not a constructor
The package is identical between both (#v2.1.1, the latest). I'm importing using ESM syntax, so:
import { Device } from '#twilio/voice-sdk'
I trying using CommonJS syntax (require) and it still didn't work. I've dug into the compiled code, and that seems to be the issue. I imagine there are a lot of differences, but one that I've noticed is here:
On the left is the code compiled by Create React App, which does seem to be exporting something more substantial than on the left - is the export just an empty object? If so, it's no wonder I'm getting a constructor error.
Unfortunately, no amount of googling and SO sleuthing has clarified what I could do to make ParcelJS transpile this dependency properly, if that's the issue. I've tried to make the babel config for ParcelJS match CRA more closely by adding the following to a babel.config.json
{
"plugins": [
"#babel/plugin-transform-modules-commonjs"
]
}
But no luck. Any ideas from where to go from here, or is it time to switch to Webpack?
It looks like Twilio package has a problem when using Parcel 2: https://github.com/twilio/twilio-voice.js/issues/101
I'm building an ionic app and would like to add unit tests for a couple of services. I'm trying to get jest working with typescript but it doesn't seem to play well.
I'm getting this error:
/myuser/project/node_modules/#ionic/storage/dist/index.js:1
({"Object.<anonymous>":function(module,exports,require,__dirname,__filename,global,jest){import { NgModule } from '#angular/core';
^^^^^^
SyntaxError: Unexpected token import
Now I have read that you have to add the babel-plugin-transform-es2015-modules-commonjs and use that in the test env of babel. However I am using babel 7 and this plugin is not available for babel 7. Is there a different solution?
I will also provide my package.json and .babelrc below.
gist
You just need to add #ionic/storage to your transformIgnorePatterns in jest config. For example, here's mine, take note of the #ionic/storage part:
"transformIgnorePatterns": [
"node_modules/(?!#ngrx|moment|#ionic/storage|#ionic-native)"
]
Additionally, make sure in your tsconfig compiler options you have module: 'commonjs'
Also, if you need localstorage mocks, you can just use the following npm module:
npm install --save-dev jest-localstorage-mock
and then (in your setupJest.ts file)
import 'jest-localstorage-mock
Lastly, I recommend taking a look at:
https://github.com/thymikee/jest-preset-angular
for more help with jest + ionic configurations.
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.
I've got a file named index.js which looks like this:
import Backbone from 'backbone'
import _ from 'underscore'
import $ from 'jquery'
console.log("blah")
export default {...}
In my index.html I've got:
<script>
System.import('index');
</script>
But what's baffling me is that I can see the file being loaded (in the dev tools network panel) but the console.log is never run. If this is the case, how am I to bootstrap my application?
Several online tutorials suggest bootstrapping it in the System.import file but how can that be done if the code isn't executed?
I ended up adding a .then() to the System.import with three anonymous functions, all with just a debugger and found that the import $ from 'jquery' was timing out because I didn't have the library installed. I removed the import declaration and the app was still trying to load jquery, so I installed it and it fixed the issue.
I am trying to import famous into my application
When i create a breakpoint in the base index.html file in ember cli and look at what require seems to know about i see famo.us is there
in my brocfile i have tried the following
app.import('vendor/famous/famous.js', {
'famous/core/Context':''
});
app.import('vendor/famous/famous.js', {
'famous/core/Context':'default'
});
app.import('vendor/famous/famous.js');
this may be fixed by master of loader.js https://github.com/stefanpenner/loader.js/issues/25