tell me how to solve the problem with the tests
my main js (activeBtnClick.js):
export default function activeButtonClick (button) {
if (button.classList.contains ( 'active')) {
button.classList.remove ( 'active');
} else {
button.classList.add ( 'active');
activeBtnClick.test.js – test:
const activeButtonClick = require ( './ activeBtnClick');
describe ( "activeBtnClick", () = & gt; {
const pencil = document.createElement ( 'div');
activeButtonClick (pencil);
it ( "add class to the button", () = & gt; {
. I expect (pencil.classList.contains ( 'active')) toEqual (true);
jest.config.js HAS NO
babel NOT use
use webpack
package.json:
"Name": "simple-piskel-clone",
"Version": "1.0.0",
"Description": "Simple Piskel Clone",
"Main": "index.js",
"scripts": {
"Test": "Echo \" error: no test specified \ "& amp; & amp; exit 1",
"Build": "webpack",
"Watch": "webpack --watch",
"Test": "jest"
"Author": "",
"License": "ISC",
"DevDependencies": {
"Css-loader": "^ 3.4.0",
"Eslint-loader": "^ 3.0.3",
"Html-webpack-plugin": "^ 3.2.0",
"Jest": "^ 24.9.0",
"Node-sass": "^ 4.13.0",
"Sass-loader": "^ 8.0.0",
"Style-loader": "^ 1.1.1",
"Url-loader": "^ 3.0.0",
"Webpack": "^ 4.41.4",
"Webpack-cli": "^ 3.3.10"
"Dependencies": {
"Eslint": "^ 6.8.0",
"Eslint-config-airbnb-base": "^ 14.0.0",
"Eslint-plugin-import": "^ 2.19.1"
Error:
Answer 1, Authority 100%
Apparently, Jest without Babel does not understand the ESM (import and export is the syntax ECMAScript Modules) – then, in the syntax CommonJS be so:
module.exports = function activeButtonClick () {...}
const activeButtonClick = require ( './ activeBtnClick.js');
Answer 2
has worked like that for me.
npx mocha --require ts-node / register --require esm src / ** / *. Spec.ts
or package.json scripts (both options work, use one that is more like it):
"scripts": {
"Test": "mocha -r esm -r ts-node / register src / ** / * spec.ts.",
"Test-ts": "ts-mocha -r esm -p tsconfig.json src / ** / * spec.ts."
The main thing do not forget to add a esm to devDependencies :
npm install --save-dev esm
In order to package.json was
"devDependencies": {
"Esm": "^ 3.2.25"
If you use the ts-mocha is it just to add to the package.json .
