Daniel Nass danielnass

Jest Testing Examples

Common Use Cases
Check if an Object contains multiple keys

Cloudflare fragment rendering/caching

This worker script will evaluate your origin response, and replace html comments marked as fragment:key with a respective prefetch defined in a X-Fragments response header.

Usage

Your origin must include the X-Fragments header, specifying the a comma separated list of prefetch requests to make for that response.

< HTTP/1.1 200 OK

This is tutorial of onfiguring eslint, prettier for your project

Make your code great again

Eslint

First of all we need to install eslint and configs as dev dependencies. You can use your own config, but I will use config from airbnb:

yarn add -D eslint eslint-config-airbnb eslint-plugin-import eslint-plugin-jsx-a11y eslint-plugin-react

Pure ESM package

The package that linked you here is now pure ESM. It cannot be require()'d from CommonJS.

This means you have the following choices:

Use ESM yourself. (preferred)
Use import foo from 'foo' instead of const foo = require('foo') to import the package. You also need to put "type": "module" in your package.json and more. Follow the below guide.
If the package is used in an async context, you could use await import(…) from CommonJS instead of require(…).
Stay on the existing version of the package until you can move to ESM.

Configuring Jest Tests in GitLab CI

1. Add GitLab CI configuration file in the root

In the root of your project, add .gitlab-ci.yml with the configuration below.

image: node:latest

stages:

Cheat sheet: Arrays

JavaScript Arrays are a very flexible data structure and used as lists, stacks, queues, tuples (e.g. pairs), etc. Some

Using Arrays

Creating Arrays, reading and writing elements:


	module.exports = {
	entry: {
	main: path.resolve(__dirname, 'src/index.js'),
	ProductList: path.resolve(__dirname, 'src/ProductList/ProductList.js'),
	ProductPage: path.resolve(__dirname, 'src/ProductPage/ProductPage.js'),
	Icon: path.resolve(__dirname, 'src/Icon/Icon.js'),
	},
	output: {
	path: path.resolve(__dirname, 'dist'),

	<!DOCTYPE html>
	<html>
	<head>
	<title>Caesar Cipher</title>

	<style type="text/css">
	body {
	margin: 0 auto;
	max-width: 40em;
	width: 88%;

	// usage examples

	// callback
	const err1 = await waitError(() => { /* do something that throws */ })

	// async callback
	const err2 = await waitError(async () => { /* do something async that throws */ })

	// expect a promise instance to throw
	const err3 = await waitError(promise)

	import {
	queryByLabelText,
	queryByRole,
	queryByText,
	} from "@testing-library/dom";
	import type { ByRoleOptions, Matcher } from "@testing-library/dom";

	const roles = [
	"alert",
	"alertdialog",