What is the minimum Node version supported by GOV.UK Frontend v5?

[paulrobertlloyd]

The package.json for govuk-frontend suggests it is v4.2.0:

govuk-frontend/packages/govuk-frontend/package.json

Line 27 in 72c543a

"node": ">= 4.2.0"

This seems unlikely at the best of times given the wondrous world of dependencies in Node, but my suspicion that this is incorrect was further heightened when I spotted that rollup v4.1.4 is listed as a dependency, and that only supports Node versions greater than 18.

Does the engines.node value in package.json need to be updated, and is v18 (moving to maintenance in the coming days) the correct minimum supported version?

[colinrotherham]

Morning @paulrobertlloyd

This came up recently in 60174e1 as we're aware that some shipped features need:

• Node.js v12.16.0 for conditional package exports
• Node.js v12.17.0 for ES modules as *.mjs
• Node.js v12.17.0 for subpath package exports
• Node.js v12.20.0 for wildcard package exports

But during code review we discussed it further and decided a Node.js restriction wasn't necessary (yet)

Recommendations

That said, we've shipped package entry points since GOV.UK Frontend v4.1.0 and fixed "subpath export" snags for both Node.js and tools following Node.js package resolution rules—but these are optional features

Node.js v4.2.0 users could still use our Rollup UMD bundles (CommonJS compatible) so we currently recommend:

If you have not already installed version 4.2.0 or later of Node.js, install the latest Long Term Support (LTS) version.

But will soon recommend:

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.

Published code

For context, we don't npm publish any package.json dependencies so we're not tied to minimum versions:

1. Node.js >=18.0.0 for rollup@^4.1.4
2. Node.js >=6.9.0 for babel@^7.23.2
3. Node.js >=14.0.0 for sass-embedded^1.69.2
4. Node.js ^14 for cssnano@^6.0.1

i.e. Our published code is already compiled/transpiled/optimised so doesn't need these tools anymore

[paulrobertlloyd]

Ah, of course, all things are not what they seem. Thanks so much for the detailed answer, @colinrotherham. Will close this issue.