Add directory listing helpers getDirectories(), getFiles(), `getL…

…isting()`

Preparation for tests that need to filter components by certain files, for example “All components with `${component}.mjs`”

lib/file-helper.js

@@ -1,45 +1,83 @@
-const fs = require('fs')
+const { readdirSync, readFileSync, statSync } = require('fs')
 const path = require('path')
 const yaml = require('js-yaml')
 const fm = require('front-matter')
 
 const configPaths = require('../config/paths.js')
 
-const childDirectories = dir => {
-  return fs.readdirSync(dir)
-    .filter(file => fs.statSync(path.join(dir, file)).isDirectory())
+/**
+ * Directory listing for path
+ *
+ * @param {string} directoryPath
+ * @returns {{ basename: string; stats: import('fs').Stats }[]} entries
+ */
+const getListing = (directoryPath) => {
+  const listing = readdirSync(directoryPath)
+
+  // Loop through listing entries
+  return listing.map(basename => ({
+    basename, stats: statSync(path.join(directoryPath, basename))
+  }))
 }
 
-// Generate component list from source directory, excluding anything that's not
-// a directory (for example, .DS_Store files)
-exports.allComponents = childDirectories(configPaths.components)
+/**
+ * Directory listing (directories only)
+ *
+ * @param {string} directoryPath
+ * @returns {string[]} directories
+ */
+const getDirectories = (directoryPath) => {
+  const entries = getListing(directoryPath)
 
-// Read the contents of a file from a given path
-const readFileContents = filePath => {
-  return fs.readFileSync(filePath, 'utf8')
+  return entries
+    .filter(({ stats }) => stats.isDirectory())
+    .map(({ basename: directory }) => directory)
 }
 
-exports.readFileContents = readFileContents
+/**
+ * Directory listing (files only)
+ *
+ * @param {string} directoryPath
+ * @returns {string[]} directories
+ */
+const getFiles = (directoryPath) => {
+  const entries = getListing(directoryPath)
+
+  return entries
+    .filter(({ stats }) => stats.isFile())
+    .map(({ basename: file }) => file)
+}
+
+// Generate component list from source directory, excluding anything that's not
+// a directory (for example, .DS_Store files)
+const allComponents = getDirectories(configPaths.components)
 
 const getComponentData = componentName => {
   try {
     const yamlPath = path.join(configPaths.components, componentName, `${componentName}.yaml`)
     return yaml.load(
-      fs.readFileSync(yamlPath, 'utf8'), { json: true }
+      readFileSync(yamlPath, 'utf8'), { json: true }
     )
   } catch (error) {
     throw new Error(error)
   }
 }
 
-exports.getComponentData = getComponentData
-
-exports.fullPageExamples = () => {
-  return childDirectories(path.resolve(configPaths.fullPageExamples))
+const fullPageExamples = () => {
+  return getDirectories(path.resolve(configPaths.fullPageExamples))
     .map(folderName => ({
       name: folderName,
       path: folderName,
-      ...fm(readFileContents(path.join(configPaths.fullPageExamples, folderName, 'index.njk'))).attributes
+      ...fm(readFileSync(path.join(configPaths.fullPageExamples, folderName, 'index.njk'), 'utf8')).attributes
     }))
     .sort((a, b) => (a.name.toLowerCase() > b.name.toLowerCase()) ? 1 : -1)
 }
+
+module.exports = {
+  allComponents,
+  fullPageExamples,
+  getComponentData,
+  getDirectories,
+  getFiles,
+  getListing
+}

tasks/gulp/__tests__/after-build-dist.test.js

@@ -1,8 +1,9 @@
+const { readFile } = require('fs/promises')
 const path = require('path')
-const lib = require('../../../lib/file-helper')
-const configPaths = require('../../../config/paths.js')
 const recursive = require('recursive-readdir')
 
+const configPaths = require('../../../config/paths.js')
+
 describe('dist/', () => {
   const version = require(path.join('../../../', configPaths.package, 'package.json')).version
 
@@ -54,7 +55,11 @@ describe('dist/', () => {
   })
 
   describe(`govuk-frontend-${version}.min.css`, () => {
-    const stylesheet = lib.readFileContents(path.join(configPaths.dist, `govuk-frontend-${version}.min.css`))
+    let stylesheet
+
+    beforeAll(async () => {
+      stylesheet = await readFile(path.join(configPaths.dist, `govuk-frontend-${version}.min.css`), 'utf8')
+    })
 
     it('should not contain current media query displayed on body element', () => {
       expect(stylesheet).not.toMatch(/body:before{content:/)
@@ -66,15 +71,23 @@ describe('dist/', () => {
   })
 
   describe(`govuk-frontend-ie8-${version}.min.css`, () => {
-    const stylesheet = lib.readFileContents(path.join(configPaths.dist, `govuk-frontend-ie8-${version}.min.css`))
+    let stylesheet
+
+    beforeAll(async () => {
+      stylesheet = await readFile(path.join(configPaths.dist, `govuk-frontend-ie8-${version}.min.css`), 'utf8')
+    })
 
     it('should not contain current media query displayed on body element', () => {
       expect(stylesheet).not.toMatch(/body:before{content:/)
     })
   })
 
   describe(`govuk-frontend-${version}.min.js`, () => {
-    const javascript = lib.readFileContents(path.join(configPaths.dist, `govuk-frontend-${version}.min.js`))
+    let javascript
+
+    beforeAll(async () => {
+      javascript = await readFile(path.join(configPaths.dist, `govuk-frontend-${version}.min.js`), 'utf8')
+    })
 
     it('should have the correct version name', () => {
       expect(javascript).toBeTruthy()