Allow Node.js LTS ‘Iron’ (v20) release version

[colinrotherham]

This PR allows Node.js LTS ‘Iron’ (v20) to install, run and build GOV.UK Frontend

GOV.UK Frontend requires Node.js version 12.17.0 or later to support ECMAScript modules. Where possible, we recommend you install the latest Long Term Support (LTS) version

Changes included:

1. Updating .browserslistrc for Node.js 20
   So Babel is aware we need to support only node 20

2. Updating .nvmrc for Node.js 20
   So tools like nvm and asdf allow the lts/iron LTS release

3. Bump the package.json engines.node range
   Ensures npm install and other scripts check the local Node.js version is allowed

4. Bump the package.json engines.npm range
   Ensure support for npm@10 rather than npm@9

[github-actions]

📋 Stats

File sizes

File	Size
dist/govuk-frontend-5.0.0-beta.0.min.css	114 KiB
dist/govuk-frontend-5.0.0-beta.0.min.js	37.85 KiB
packages/govuk-frontend/dist/govuk/all.bundle.js	77.08 KiB
packages/govuk-frontend/dist/govuk/all.bundle.mjs	72.37 KiB
packages/govuk-frontend/dist/govuk/all.mjs	3.8 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend-component.mjs	359 B
packages/govuk-frontend/dist/govuk/govuk-frontend.min.css	113.99 KiB
packages/govuk-frontend/dist/govuk/govuk-frontend.min.js	37.92 KiB
packages/govuk-frontend/dist/govuk/i18n.mjs	5.3 KiB

Modules

File	Size
all.mjs	68.7 KiB
components/accordion/accordion.mjs	21.35 KiB
components/button/button.mjs	4.48 KiB
components/character-count/character-count.mjs	20.79 KiB
components/checkboxes/checkboxes.mjs	5.61 KiB
components/error-summary/error-summary.mjs	5.79 KiB
components/exit-this-page/exit-this-page.mjs	15.79 KiB
components/header/header.mjs	3.68 KiB
components/notification-banner/notification-banner.mjs	4.32 KiB
components/radios/radios.mjs	4.6 KiB
components/skip-link/skip-link.mjs	3.6 KiB
components/tabs/tabs.mjs	9.37 KiB

View stats and visualisations on the review app

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Action run for 19173ea

[colinrotherham]

Blocked until Node.js 20 LTS released: 24 October 2023

[colinrotherham]

Heroku builds are still failing, must still be rolling out:

-----> Installing binaries
       engines.node (package.json):  ^20.9.0
       engines.npm (package.json):   ^10.1.0
       
       Resolving node version ^20.9.0...
       Could not find Node version corresponding to version requirement: ^20.9.0
-----> Build failed
 !     No matching version found for Node: ^20.9.0

We'll keep an eye on the Heroku Changelog

[colinrotherham]

All sorted, Heroku is ready to go:

Node.js 20.9.0 and 21.1.0 now available
Node.js versions 20.9.0 and 21.1.0 have been made available for builds on Heroku. For additional information, please see our article on Node.js Support.

[colinrotherham]

From our "waiting for" list in #4201 (comment) it looks like we're just missing asdf support:

• Add NodeJS LTS 20 series asdf-vm/asdf-nodejs#377

[romaricpascal]

Looking good. nvm was happy with lts/iron locally (and Github actions and Heroku) on CI, hopefully asdf won't be long.

Do you know if people will need to update asdf locally for it to undersand lts/iron?

[colinrotherham]

@romaricpascal Nah it does an automatic update on asdf install

Wonder if we should use 20.x or something similarly compatible instead of code names?

[romaricpascal]

20.x sounds a great way to not make us depend on the tools understanding the latest code name, so very up for that 😊

[romaricpascal]

From our discussion on Slack, it seems using 20 in .nvmrc causes trouble with asdf when Husky runs. That'd make lts/iron would be fine once asdf supports it, unless we figure why Husky and asdf don't play nicely.

It'll also be worth coordinating the merge with the rest of the team, so that people know to run nvm or asdf to set up the new version.

[colinrotherham]

Thanks @romaricpascal

Let's stick with lts/hydrogen lts/iron now that asdf-vm/asdf-nodejs#377 has merged

Node.js version managers

I've added some notes for typical macOS + ZSH + Homebrew installs

For Node.js commit hook support via GUI (e.g. Tower) duplicate these changes into ~/.huskyrc

Using nvm

Check for updates using README Install & Update Script and check these lines are in ~/.zshrc

export NVM_DIR="$([ -z "${XDG_CONFIG_HOME-}" ] && printf %s "${HOME}/.nvm" || printf %s "${XDG_CONFIG_HOME}/nvm")"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh" # This loads nvm

Running nvm install will automatically download Node.js LTS v20.9.0

Using asdf

Check the Node.js asdf plugin is up to date via asdf plugin-update nodejs and these lines are in ~/.zshrc

# Resolves 'lts/iron' → 20 → 20.9.0
export ASDF_NODEJS_LEGACY_FILE_DYNAMIC_STRATEGY=latest_available

. $(brew --prefix asdf)/libexec/asdf.sh

After setting ASDF_NODEJS_LEGACY_FILE_DYNAMIC_STRATEGY in ~/.zshrc we can opt in to "legacy version file" .nvmrc config support (see README Partial and codename versions) using the following ~/.asdfrc config line:

legacy_version_file = yes

Once both are set, asdf is able to expand codenames lts/iron and partial versions 18, 20, 20.9 etc into full 20.9.0 version numbers to avoid error messages such as:

No preset version installed for command npx
Please install a version by running one of the following:

asdf install nodejs 20

or add one of the following versions in your config file at /Users/username/.tool-versions
nodejs 18.18.2
nodejs 20.9.0
nodejs lts-iron

Running asdf install will automatically download Node.js LTS v20.9.0