Support version number via prototypeKitVersion local etc (#230)

This PR adds a new locals to migrate the `{{ version }}` number from

```
prototypeKitVersion
nhsukFrontendVersion
```

Unblocks #239

<img width="819" height="219" alt="Version numbers displayed in test
app"
src="https://github.com/user-attachments/assets/a2761401-33d8-4bae-909b-4fcdeaa3b017"
/>

---

## Config export

I've also added `config` alongside exported `middleware`,
`nunjucksFilters` and `utils`

### ES module named export

```mjs
import { config } from 'nhsuk-prototype-kit'

config.prototypeKitVersion
config.nhsukFrontendVersion
config.searchPaths
```

### ES module package export

```mjs
import * as config from 'nhsuk-prototype-kit/config'

config.prototypeKitVersion
config.nhsukFrontendVersion
config.searchPaths
```

### CommonJS package export

```mjs
const config = require('nhsuk-prototype-kit/config')

config.prototypeKitVersion
config.nhsukFrontendVersion
config.searchPaths
```

### CommonJS static properties

```cjs
const NHSPrototypeKit = require('nhsuk-prototype-kit')

const { config } = NHSPrototypeKit

config.prototypeKitVersion
config.nhsukFrontendVersion
config.searchPaths
```

Author: colinrotherham

CHANGELOG.md

@@ -10,6 +10,7 @@
 - Add link to "/" from header
 - Update error pages to use nhsuk-heading-l
 - Support NHS.UK frontend v11.x previews and pre-releases
+- Support version number via `prototypeKitVersion` local
 
 ## 8.0.1 – 6 Feb 2026
 

lib/esbuild.config.js

@@ -1,10 +1,7 @@
-import { join } from 'node:path'
-import { cwd } from 'node:process'
-
 import { cleanPlugin } from 'esbuild-clean-plugin'
 import { sassPlugin } from 'esbuild-sass-plugin'
 
-import { modulesPath } from './nhsuk-prototype-kit.config.js'
+import * as config from './nhsuk-prototype-kit.config.js'
 
 const { NODE_ENV } = process.env
 
@@ -25,7 +22,7 @@ export default /** @satisfies {BuildOptions} */ ({
     cleanPlugin(),
     sassPlugin({
       embedded: true,
-      loadPaths: [modulesPath, join(cwd(), 'node_modules')],
+      loadPaths: config.modulePaths,
       silenceDeprecations: ['import'],
       quietDeps: true,
       sourceMap: true,

lib/index.js

@@ -1,10 +1,11 @@
 import * as middleware from './middleware/index.js'
+import * as config from './nhsuk-prototype-kit.config.js'
 import { NHSPrototypeKit } from './nhsuk-prototype-kit.js'
 import * as nunjucksFilters from './nunjucks-filters/index.js'
 import * as utils from './utils/index.js'
 
 export default NHSPrototypeKit
-export { middleware, nunjucksFilters, utils }
+export { config, middleware, nunjucksFilters, utils }
 
 /**
  * @typedef {import('./nhsuk-prototype-kit.js').Options} Options

lib/index.test.cjs

@@ -5,13 +5,50 @@ const express = require('express')
 const nunjucks = require('nunjucks')
 
 const NHSPrototypeKit = require('./index.cjs')
+const { config, middleware, nunjucksFilters, utils } = NHSPrototypeKit
 
 describe('CommonJS default exports', () => {
   it('should export NHSPrototypeKit as default', () => {
     assert.ok(NHSPrototypeKit)
     assert.equal(typeof NHSPrototypeKit, 'function')
   })
 
+  it('should export config as static property', () => {
+    assert.ok(config)
+    assert.equal(typeof config, 'object')
+    assert.equal(typeof config.nhsukFrontendPath, 'string')
+    assert.equal(typeof config.nhsukFrontendVersion, 'string')
+    assert.equal(typeof config.prototypeKitPath, 'string')
+    assert.equal(typeof config.prototypeKitVersion, 'string')
+    assert.ok(config.modulePaths.every((path) => typeof path === 'string'))
+    assert.ok(config.searchPaths.every((path) => typeof path === 'string'))
+  })
+
+  it('should export middleware as static property', () => {
+    assert.ok(middleware)
+    assert.equal(typeof middleware, 'object')
+    assert.equal(typeof middleware.configure, 'function')
+    assert.equal(typeof middleware.autoRoutes, 'function')
+  })
+
+  it('should export nunjucksFilters as static property', () => {
+    assert.ok(nunjucksFilters)
+    assert.equal(typeof nunjucksFilters, 'object')
+    assert.equal(typeof nunjucksFilters.addAll, 'function')
+    assert.equal(typeof nunjucksFilters.formatNhsNumber, 'function')
+    assert.equal(typeof nunjucksFilters.log, 'function')
+    assert.equal(typeof nunjucksFilters.startsWith, 'function')
+  })
+
+  it('should export utils as static property', () => {
+    assert.ok(utils)
+    assert.equal(typeof utils, 'object')
+    assert.equal(typeof utils.addNunjucksFilters, 'function')
+    assert.equal(typeof utils.findAvailablePort, 'function')
+    assert.equal(typeof utils.getAvailablePort, 'function')
+    assert.equal(typeof utils.normaliseOptions, 'function')
+  })
+
   it('should have init method', () => {
     assert.equal(typeof NHSPrototypeKit.init, 'function')
   })

lib/index.test.js

@@ -2,6 +2,7 @@ import assert from 'node:assert/strict'
 import { describe, it } from 'node:test'
 
 import NHSPrototypeKit, {
+  config,
   middleware,
   nunjucksFilters,
   utils
@@ -13,6 +14,17 @@ describe('ES module named exports', () => {
     assert.equal(typeof NHSPrototypeKit, 'function')
   })
 
+  it('should export config as a named export', () => {
+    assert.ok(config)
+    assert.equal(typeof config, 'object')
+    assert.equal(typeof config.nhsukFrontendPath, 'string')
+    assert.equal(typeof config.nhsukFrontendVersion, 'string')
+    assert.equal(typeof config.prototypeKitPath, 'string')
+    assert.equal(typeof config.prototypeKitVersion, 'string')
+    assert.ok(config.modulePaths.every((path) => typeof path === 'string'))
+    assert.ok(config.searchPaths.every((path) => typeof path === 'string'))
+  })
+
   it('should export middleware as a named export', () => {
     assert.ok(middleware)
     assert.equal(typeof middleware, 'object')

lib/middleware/index.js

@@ -3,6 +3,8 @@ import cookieParser from 'cookie-parser'
 import flash from 'express-flash'
 import session from 'express-session'
 
+import * as config from '../nhsuk-prototype-kit.config.js'
+
 import { authentication } from './authentication.js'
 import { autoRoutes } from './auto-routes.js'
 import { autoStoreData } from './auto-store-data.js'
@@ -42,13 +44,30 @@ function generateSessionName(serviceName) {
   return `nhsuk-prototype-kit-${hash}`
 }
 
+/**
+ * Configure locals middleware
+ *
+ * @param {Options} options
+ */
+export function configureLocals(options) {
+  const { app, serviceName } = options
+
+  app.use(setCurrentPageInLocals)
+  app.use((req, res, next) => {
+    res.locals.nhsukFrontendVersion = config.nhsukFrontendVersion
+    res.locals.prototypeKitVersion = config.prototypeKitVersion
+    res.locals.serviceName = serviceName
+    next()
+  })
+}
+
 /**
  * Configure session middleware
  *
- * @param {Express} app
- * @param {string} serviceName
+ * @param {Options} options
  */
-function configureSession(app, serviceName) {
+export function configureSession(options) {
+  const { app, serviceName } = options
   const sessionName = generateSessionName(serviceName)
 
   app.use(
@@ -72,26 +91,21 @@ function configureSession(app, serviceName) {
  * @param {Options} options
  */
 export function configure(options) {
-  const app = options.app
-  const serviceName = options.serviceName || 'Service name goes here'
+  const { app } = options
 
   // Configure core middleware
   app.use(cookieParser())
   app.use(bodyParser.urlencoded({ extended: true }))
 
   // Configure session
-  configureSession(app, serviceName)
+  configureSession(options)
+
+  // Configure locals
+  configureLocals(options)
 
   // Use flash
   app.use(flash())
 
-  // Set locals
-  app.use(setCurrentPageInLocals)
-  app.use((req, res, next) => {
-    res.locals.serviceName = serviceName
-    next()
-  })
-
   // Add production-specific middleware
   if (process.env.NODE_ENV === 'production') {
     app.use(productionHeaders)
@@ -132,6 +146,5 @@ export function configure(options) {
 }
 
 /**
- * @import { Express } from 'express'
  * @import { Options } from '../nhsuk-prototype-kit.js'
  */

lib/middleware/reset-session-data.js

@@ -6,9 +6,6 @@
 export function resetSessionData(req, res, next) {
   const { path, method } = req
 
-  // Current page used for the Reset data feature
-  res.locals.currentPage = req.originalUrl
-
   if (method === 'GET' && path === '/prototype-admin/reset') {
     const returnPage = req.query.returnPage || '/'
     res.render('reset', {

lib/middleware/reset-session-data.test.js

@@ -145,17 +145,6 @@ describe('resetSessionData middleware', () => {
 
       assert.equal(next.mock.callCount(), 1)
     })
-
-    it('should set res.locals.currentPage for all requests', () => {
-      Object.assign(req, {
-        originalUrl: '/test-url?param=value',
-        path: '/some-page'
-      })
-
-      resetSessionData(req, res, next)
-
-      assert.equal(res.locals.currentPage, '/test-url?param=value')
-    })
   })
 
   describe('reset-session-data endpoint behavior', () => {

lib/nhsuk-prototype-kit.config.js

@@ -1,13 +1,47 @@
-import { dirname } from 'node:path'
+import { dirname, join } from 'node:path'
+import { cwd } from 'node:process'
 import { fileURLToPath } from 'node:url'
 
-// NHS prototype kit path
+import nhsukFrontendPkg from 'nhsuk-frontend/package.json' with { type: 'json' }
+
+import pkg from '../package.json' with { type: 'json' }
+
+/**
+ * NHS prototype kit path
+ */
 export const prototypeKitPath = dirname(import.meta.dirname)
 
-// NHS.UK frontend package path
+/**
+ * NHS prototype kit version
+ */
+export const prototypeKitVersion = `v${pkg.version}`
+
+/**
+ * NHS.UK frontend path
+ */
 export const nhsukFrontendPath = fileURLToPath(
   dirname(import.meta.resolve('nhsuk-frontend/package.json'))
 )
 
-// Node modules path
-export const modulesPath = dirname(nhsukFrontendPath)
+/**
+ * NHS.UK frontend version
+ */
+export const nhsukFrontendVersion = `v${nhsukFrontendPkg.version}`
+
+/**
+ * Node.js module paths
+ */
+export const modulePaths = Array.from(
+  new Set([dirname(nhsukFrontendPath), join(cwd(), 'node_modules')])
+)
+
+/**
+ * Nunjucks search paths
+ */
+export const searchPaths = [
+  join(prototypeKitPath, 'lib/views'),
+  join(nhsukFrontendPath, 'dist/nhsuk/components'),
+  join(nhsukFrontendPath, 'dist/nhsuk/macros'),
+  join(nhsukFrontendPath, 'dist/nhsuk'),
+  join(nhsukFrontendPath, 'dist')
+]

lib/nhsuk-prototype-kit.js

@@ -8,10 +8,7 @@ import waitOn from 'wait-on'
 import { build } from './build/index.js'
 import * as expressSettings from './express-settings/index.js'
 import * as middleware from './middleware/index.js'
-import {
-  nhsukFrontendPath,
-  prototypeKitPath
-} from './nhsuk-prototype-kit.config.js'
+import * as config from './nhsuk-prototype-kit.config.js'
 import * as nunjucksFilters from './nunjucks-filters/index.js'
 import * as utils from './utils/index.js'
 
@@ -28,6 +25,11 @@ export class NHSPrototypeKit {
     this.buildOptions = buildOptions
   }
 
+  static config = config
+  static middleware = middleware
+  static nunjucksFilters = nunjucksFilters
+  static utils = utils
+
   /**
    * This does all setup for both the Express app
    * and the Nunjucks environment
@@ -60,13 +62,13 @@ export class NHSPrototypeKit {
     // Use assets from NHS.UK frontend
     app.use(
       '/nhsuk-frontend',
-      express.static(join(nhsukFrontendPath, 'dist/nhsuk'))
+      express.static(join(config.nhsukFrontendPath, 'dist/nhsuk'))
     )
 
     // Use scripts from lib
     app.use(
       '/nhsuk-prototype-kit/javascripts',
-      express.static(join(prototypeKitPath, 'lib/javascripts'))
+      express.static(join(config.prototypeKitPath, 'lib/javascripts'))
     )
 
     // Use assets and images from public, with app fallback
@@ -243,10 +245,10 @@ export class NHSPrototypeKit {
 
 /**
  * @typedef {object} Options
- * @property {string} [serviceName] - Service name
+ * @property {string} serviceName - Service name
  * @property {Express} app - Express app
  * @property {Router} [routes] - Additional custom routes
- * @property {string | string[]} [viewsPath] - Additional custom views path
+ * @property {string | string[]} viewsPath - Additional custom views path
  * @property {RequestHandler} [locals] - Middleware to set additional locals
  * @property {Environment} nunjucks - Nunjucks environment
  * @property {NunjucksFilters | ((env: Environment) => NunjucksFilters)} [filters] - Additional custom Nunjucks filters