refactor: Do some cleaning and normalizing

src/adapter/icu.js

@@ -1,12 +1,9 @@
-import assert from 'node:assert'
-
 export const translateString = (
   (IntlMessageFormat, dictionary, defaultLocale = 'en') => (
     (msgID, params = {}, locale = defaultLocale) => {
-      assert(
-        msgID in dictionary,
-        `The messsage with ID \`${msgID}\` does not exist in the dictionary.`,
-      )
+      if (!(msgID in dictionary)) {
+        throw new RangeError(`The messsage with ID \`${msgID}\` does not exist in the dictionary.`)
+      }
 
       return new IntlMessageFormat(dictionary[msgID], locale).format(params)
     }

src/domain/data.js

@@ -1,14 +1,12 @@
 const DATA_FILE_PATH = 'data.json'
 const ENV_VAR_PLACEHOLDER_PATTERN = /^%(.+)%$/
 
-const captureEnvVarName = (value) => {
-  const match = value.match?.(ENV_VAR_PLACEHOLDER_PATTERN)
-
-  return match ? match[1] : null
-}
+const captureEnvVarName = (value) => value.match?.(ENV_VAR_PLACEHOLDER_PATTERN)?.[1] ?? null
 
 export const parseProjectData = (parseJSONFile, withSrcDir) => (
-  withSrcDir((prefixWithSrcDir) => parseJSONFile(prefixWithSrcDir(DATA_FILE_PATH)))
+  withSrcDir(
+    (prefixWithSrcDir) => parseJSONFile(prefixWithSrcDir(DATA_FILE_PATH))
+  )
 )
 
 export const mergeDataWithEnvVars = (

src/domain/i18n.js

@@ -1,4 +1,3 @@
-import assert from 'node:assert'
 import { join } from 'node:path'
 
 const LANG_PATTERN = /^[a-z]{2}$/
@@ -8,7 +7,9 @@ const TRANSLATION_FILE_EXT = '.json'
 export const parseProjectTranslations = (
   (parseJSONFile, withSrcDir, dotFlattenObject) => (
     (lang) => {
-      assert.match(lang, LANG_PATTERN, `\`${lang}\` is not a valid language code.`)
+      if (!LANG_PATTERN.test(lang)) {
+        throw new Error(`\`${lang}\` is not a valid language code.`)
+      }
 
       return withSrcDir((prefixWithSrcDir) => {
         const translationFilePath = join(

src/main.js

@@ -30,14 +30,13 @@ export default async function main(
   lang = null,
   envVars = {},
 ) {
-  const _parseJSONFile = parseJSONFile(ifPathExists, readFile)
-
   await ifPathExists(buildDirPath, rmDir)
 
   const [withSrcDir, withBuildDir] = await Promise.all([
     withDir(srcDirPath),
     withScratchDir(buildDirPath),
   ])
+  const _parseJSONFile = parseJSONFile(ifPathExists, readFile)
 
   return (
     Promise.all([

src/utils/fs.js

@@ -1,15 +1,14 @@
-import assert from 'node:assert'
 import * as fs from 'node:fs/promises'
 import { join } from 'node:path'
 
+const prefixWithDir = (dirPath) => (relativePath = '') => join(dirPath, relativePath)
+
 export const withDir = (
   (dirPath) => (
     async (cb) => {
       await fs.access(dirPath)
 
-      const prefixWithDir = (relativePath = '') => join(dirPath, relativePath)
-
-      return cb(prefixWithDir)
+      return cb(prefixWithDir(dirPath))
     }
   )
 )
@@ -29,9 +28,7 @@ export const withScratchDir = (
 
       await fs.access(dirPath, fs.constants.W_OK)
 
-      const prefixWithDir = (relativePath = '') => join(dirPath, relativePath)
-
-      return cb(prefixWithDir)
+      return cb(prefixWithDir(dirPath))
     }
   )
 )
@@ -59,7 +56,9 @@ export const copyDir = (srcPath, destPath) => (
 )
 
 export const rmDir = (path) => {
-  assert.notStrictEqual(path, '/', 'Removing the filesystem’s root is not allowed.')
+  if (path === '/') {
+    throw new SystemError('Removing the filesystem’s root is not allowed.')
+  }
 
   return fs.rm(path, { recursive: true })
 }

src/utils/json.js

@@ -1,9 +1,9 @@
 export const parseJSONFile = (
   (ifPathExists, readFile) => (
-    (filePath) => (
+    (jsonFilePath) => (
       ifPathExists(
-        filePath,
-        () => readFile(filePath).then(JSON.parse),
+        jsonFilePath,
+        (filePath) => readFile(filePath).then(JSON.parse),
         {},
       )
     )

src/utils/object.js

@@ -1,21 +1,14 @@
-import assert from 'node:assert'
+const PROP_PATH_PATTERN = /^(?<currentKey>[a-z_]+)(?<rest>(?:\.[a-z_]+)*)$/i
 
-const valueIsObject = (value) => (
-  typeof value !== 'undefined' &&
-  value.constructor.name === 'Object'
-)
+const valueIsObject = (value) => value.constructor?.name === 'Object'
 
-const valueIsArray = (value) => (
-  typeof value !== 'undefined' &&
-  value.constructor.name === 'Array'
-)
+const valueIsArray = (value) => value.constructor?.name === 'Array'
 
 const valueIsComposite = (value) => valueIsObject(value) || valueIsArray(value)
 
-const testPropPathValidity = (propPath) => (
-  /^(?<currentKey>[a-z_]+)(?<rest>(?:\.[a-z_]+)*)$/i
-    .exec(propPath)
-)
+const objectIsEmpty = (obj) => Object.keys(obj).length > 0
+
+const matchPropPath = (propPath) => propPath.match?.(PROP_PATH_PATTERN) ?? null
 
 export const deepCloneObject = (obj) => JSON.parse(JSON.stringify(obj))
 
@@ -35,37 +28,42 @@ export const transformObjectValues = (obj, cb) => {
   return obj
 }
 
-export const cleanUpObjectList = (objectList) => objectList.filter((obj) => Object.keys(obj).length)
+export const cleanUpObjectList = (objectList) => objectList.filter(objectIsEmpty)
 
 export const mergeObjectList = (objectList) => Object.assign({}, ...objectList)
 
 export const accessObjectProp = (obj, propPath) => {
-  const match = testPropPathValidity(propPath)
+  const match = matchPropPath(propPath)
 
-  assert.notStrictEqual(match, null, `The property path \`${propPath}\` is invalid.` )
+  if (match === null) {
+    throw new Error(`The property path \`${propPath}\` is invalid.` )
+  }
 
   const currentKey = match.groups.currentKey
 
-  if (typeof obj[currentKey] === 'undefined') {
+  if (!(currentKey in obj)) {
     throw new RangeError(`The key \`${currentKey}\` does not exist in the current object tree.`)
   }
 
   const rest = match.groups.rest
   const hasRest = Boolean(rest.length)
+  const currentValue = obj[currentKey]
 
-  if (hasRest && !valueIsObject(obj[currentKey])) {
+  if (hasRest && !valueIsObject(currentValue)) {
     throw new TypeError(`The value at key \`${currentKey}\` is not an object and can’t be traversed.`)
   }
 
   return (
     hasRest
-      ? accessObjectProp(obj[currentKey], rest.substring(1))
-      : obj[currentKey]
+      ? accessObjectProp(currentValue, rest.substring(1))
+      : currentValue
   )
 }
 
 export const dotFlattenObject = (obj) => {
-  assert(valueIsComposite(obj), 'Only composite values can be flattened.')
+  if (!valueIsComposite(obj)) {
+    throw new TypeError('Only composite values can be flattened.')
+  }
 
   const output = {}
 

tests/adapter/icu.test.js

@@ -11,7 +11,7 @@ describe('#src/adapter/icu', () => {
         occupation: 'I’m a {job}, the best in {town}.',
         number_of_kids: 'I have {kidNum, plural, =0 {no kids} =1 {a single child} other {# kids}}.',
         bastille_day: 'France’s Bastille Day was on {bastilleDay, date, ::yyyyMMMMdd}.',
-        account_balance: 'I have {balance, number} moneyz on my bank account.'
+        account_balance: 'I have {balance, number} moneyz on my bank account.',
       }
 
       const trans = translateString(IntlMessageFormat, dictionary)

tests/domain/data.test.js

@@ -10,7 +10,7 @@ import { parseProjectData, mergeDataWithEnvVars } from '#src/domain/data'
 
 describe('#src/domain/data', () => {
   describe('parseProjectData()', () => {
-    it('parses data from a `data.json` file at project root', async () => {
+    it('parses data from a `data.json` file at the project root', async () => {
       await withTempDir(async (prefixWithTempDir) => {
         const srcDirPath = prefixWithTempDir('src')
         const dataFilePath = join(srcDirPath, 'data.json')
@@ -46,7 +46,7 @@ describe('#src/domain/data', () => {
             42,
             '%SECRET_PHONE_NUMBER%',
             false,
-            'LANG'
+            'LANG',
           ],
         },
         cruft: {
@@ -55,6 +55,7 @@ describe('#src/domain/data', () => {
             lang: '%LANG%',
             phone: 'SECRET_PHONE_NUMBER',
           },
+          nil: '%NOPE%',
         },
       }
 
@@ -74,7 +75,7 @@ describe('#src/domain/data', () => {
               42,
               '+33700000000',
               false,
-              'LANG'
+              'LANG',
             ],
           },
           cruft: {
@@ -83,6 +84,7 @@ describe('#src/domain/data', () => {
               lang: 'fr',
               phone: 'SECRET_PHONE_NUMBER',
             },
+            nil: null,
           },
         },
       )

tests/domain/i18n.test.js

@@ -47,12 +47,10 @@ describe('#src/domain/i18n', () => {
 }
 `)
 
-        const withSrcDir = withDir(srcDirPath)
-        const _parseJSONFile = parseJSONFile(ifPathExists, readFile)
         const _parseProjectTranslations = (
           parseProjectTranslations(
-            _parseJSONFile,
-            withSrcDir,
+            parseJSONFile(ifPathExists, readFile),
+            withDir(srcDirPath),
             dotFlattenObject,
           )
         )
@@ -83,10 +81,7 @@ describe('#src/domain/i18n', () => {
     })
 
     it('throws if an invalid `lang` parameter is passed', () => {
-      assert.throws(
-        () => parseProjectTranslations(noop, noop, noop)('fAiL'),
-        assert.AssertionError,
-      )
+      assert.throws(() => parseProjectTranslations(noop, noop, noop)('fAiL'))
     })
   })
 })

tests/utils/fs.test.js

@@ -78,8 +78,8 @@ describe('#src/utils/fs', () => {
       const nonExistentPath = generateNonExistentPath()
       let marker = 0
 
-      await ifPathExists('/', () => marker = 1)
-      await ifPathExists(nonExistentPath, () => marker = 2)
+      await ifPathExists('/', (_) => marker = 1)
+      await ifPathExists(nonExistentPath, (_) => marker = 2)
 
       assert.strictEqual(marker, 1)
     })
@@ -185,5 +185,9 @@ describe('#src/utils/fs', () => {
         await assert.rejects(fs.access(dirPath))
       })
     })
+
+    it('prevents the deletion of the filesystem’s root', {
+      skip: 'This is too scary to test 😱 (disk wipe hazard).',
+    })
   })
 })

tests/utils/object.test.js

@@ -60,10 +60,10 @@ describe('#src/utils/object', () => {
   describe('transformObjectValues()', () => {
     it('recursively passes each of an object’s nested values trough a callback', () => {
       const obj = {
-        foo: 'bar',
+        foo: 42,
         stuff: [
           'foo',
-          'bar',
+          Symbol.for('clutter'),
           {
             some_prop: 'a',
             other_prop: 'b',
@@ -90,10 +90,10 @@ describe('#src/utils/object', () => {
       assert.deepStrictEqual(
         transformObjectValues(obj, transformer),
         {
-          foo: 'BAR',
+          foo: 42,
           stuff: [
             'FOO',
-            'BAR',
+            Symbol.for('clutter'),
             {
               some_prop: 'A',
               other_prop: 'B',
@@ -112,6 +112,17 @@ describe('#src/utils/object', () => {
         },
       )
     })
+
+    it('throws if not passed a composite value', () => {
+      assert.throws(
+        () => dotFlattenObject(3.14),
+        TypeError,
+      )
+      assert.throws(
+        () => dotFlattenObject(Symbol.for('foobar')),
+        TypeError,
+      )
+    })
   })
 
   describe('cleanUpObjectList()', () => {
@@ -127,6 +138,7 @@ describe('#src/utils/object', () => {
         {
           stuff: 'clutter',
         },
+        {},
       ]
 
       assert.deepStrictEqual(
@@ -170,7 +182,7 @@ describe('#src/utils/object', () => {
           identity: {
             name: 'John',
             surname: 'Doe',
-          }
+          },
         }
       )
     })
@@ -192,10 +204,7 @@ describe('#src/utils/object', () => {
     })
 
     it('throws if the property path is invalid', () => {
-      assert.throws(
-        () => accessObjectProp({}, '379&239--'),
-        assert.AssertionError,
-      )
+      assert.throws(() => accessObjectProp({}, '379&239--'))
     })
 
     it('throws if one of the nested properties does not exist or is not an object', () => {
@@ -248,11 +257,11 @@ describe('#src/utils/object', () => {
     it('throws if not passed a composite value', () => {
       assert.throws(
         () => dotFlattenObject(42),
-        assert.AssertionError,
+        TypeError,
       )
       assert.throws(
         () => dotFlattenObject('Hello!'),
-        assert.AssertionError,
+        TypeError,
       )
     })
   })