refactor: Fix some quirks in async flow

fabschurt · Jun 27, 2023 · 58d3b8f · 58d3b8f
1 parent 75de935
commit 58d3b8f
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Showing 5 changed files with 43 additions and 40 deletions.
diff --git a/src/data.js b/src/data.js
@@ -9,16 +9,16 @@ function normalizeEnvVarName(str) {
   )
 }
 
-export async function parseDataFromJsonFile(
+export function parseDataFromJsonFile(
   withSrcDir,
   ifPathExists,
   readFile,
   parseJson,
 ) {
-  return await withSrcDir(async (prefixWithSrcDir) => {
+  return withSrcDir((prefixWithSrcDir) => {
     const jsonFilePath = prefixWithSrcDir(JSON_FILE_NAME)
 
-    return await ifPathExists(
+    return ifPathExists(
       jsonFilePath,
       async () => parseJson(await readFile(jsonFilePath)),
       {},

diff --git a/src/i18n.js b/src/i18n.js
@@ -5,7 +5,7 @@ const LANG_PATTERN = /^[a-z]{2}$/
 const TRANSLATION_DIR_PATH = 'i18n'
 const TRANSLATION_FILE_PREFIX = '.json'
 
-export async function parseTranslations(
+export function parseTranslations(
   withSrcDir,
   ifPathExists,
   readFile,
@@ -14,16 +14,16 @@ export async function parseTranslations(
 ) {
   assert.match(lang, LANG_PATTERN)
 
-  return await withSrcDir(async (prefixWithSrcDir) => {
+  return withSrcDir((prefixWithSrcDir) => {
     const translationFilePath = join(
       prefixWithSrcDir(TRANSLATION_DIR_PATH),
       lang + TRANSLATION_FILE_PREFIX,
     )
 
-    return await ifPathExists(
+    return ifPathExists(
       translationFilePath,
       async () => parseJson(await readFile(translationFilePath)),
-      {}
+      {},
     )
   })
 }
diff --git a/src/index.js b/src/index.js
@@ -13,20 +13,37 @@ import { parseTranslations } from '#src/i18n'
 import { parseJson } from '#src/utils/json'
 import renderTemplate from '#src/renderTemplate/pug'
 
-export default async function buildProject(srcDirPath, buildDirPath, lang = null) {
+export default async function buildProject(
+  srcDirPath,
+  buildDirPath,
+  lang = null,
+) {
   await ifPathExists(buildDirPath, rmDir)
 
-  const withSrcDir = await withDir(srcDirPath)
-  const withBuildDir = await withScratchDir(buildDirPath)
+  const [withSrcDir, withBuildDir] = await (
+    Promise.all([
+      withDir(srcDirPath),
+      withScratchDir(buildDirPath),
+    ])
+  )
 
-  const data = {
-    ...(await parseDataFromJsonFile(withSrcDir, ifPathExists, readFile, parseJson)),
-    ...parseDataFromEnv(process.env),
-  }
-
-  if (lang) {
-    data.t = await parseTranslations(withSrcDir, ifPathExists, readFile, parseJson, lang)
-  }
+  // This will fetch data from 3 different sources simultaneously, filter out
+  // empty results, and merge everything into a final single object (this is not
+  // overly readable, but it allows for «parallel» asynchronous fetching of
+  // data):
+  const data = await (
+    Promise.all([
+      parseDataFromJsonFile(withSrcDir, ifPathExists, readFile, parseJson),
+      parseDataFromEnv(process.env),
+      lang
+        ? parseTranslations(withSrcDir, ifPathExists, readFile, parseJson, lang)
+            .then((dictionary) => ({ i18n: dictionary }))
+        : {}
+      ,
+    ])
+      .then((objects) => objects.filter((obj) => Object.keys(obj).length))
+      .then((objects) => Object.assign({}, ...objects))
+  )
 
   return Promise.all([
     renderIndex(withSrcDir, withBuildDir, readFile, writeFile, renderTemplate, data),

diff --git a/tests/i18n.test.js b/tests/i18n.test.js
@@ -38,15 +38,10 @@ describe('#src/i18n', () => {
       })
     })
 
-    it('throws if an invalid `lang` parameter is passed', async () => {
-      await assert.rejects(
-        parseTranslations(
-          withDir(tmpdir()),
-          ifPathExists,
-          readFile,
-          parseJson,
-          'fAiL',
-        )
+    it('throws if an invalid `lang` parameter is passed', () => {
+      assert.throws(
+        () => parseTranslations(withDir(tmpdir()), ifPathExists, readFile, parseJson, 'fAiL'),
+        assert.AssertionError
       )
     })
   })

diff --git a/tests/utils/fs.test.js b/tests/utils/fs.test.js
@@ -1,8 +1,8 @@
 import { describe, it } from 'node:test'
 import assert from 'node:assert'
-import { withTempDir, generateNonExistentPath, noop } from '#tests/helpers'
 import * as fs from 'node:fs/promises'
 import { join } from 'node:path'
+import { withTempDir, generateNonExistentPath, noop } from '#tests/helpers'
 import {
   withDir,
   withScratchDir,
@@ -22,10 +22,7 @@ describe('#src/utils/fs', () => {
 
         await fs.mkdir(dirPath)
         await withDir(dirPath)(async (prefixWithDir) => {
-          await fs.writeFile(
-            prefixWithDir(fileName),
-            'Hello fren!',
-          )
+          await fs.writeFile(prefixWithDir(fileName), 'Hello fren!')
         })
 
         await assert.doesNotReject(fs.access(join(dirPath, fileName)))
@@ -44,10 +41,7 @@ describe('#src/utils/fs', () => {
         const fileName = 'test.txt'
 
         await withScratchDir(dirPath)(async (prefixWithDir) => {
-          await fs.writeFile(
-            prefixWithDir(fileName),
-            'All your base are belong to us.',
-          )
+          await fs.writeFile(prefixWithDir(fileName), 'All your base are belong to us.')
         })
 
         await assert.doesNotReject(fs.access(dirPath))
@@ -62,10 +56,7 @@ describe('#src/utils/fs', () => {
 
         await fs.mkdir(dirPath)
         await withScratchDir(dirPath)(async (prefixWithDir) => {
-          await fs.writeFile(
-            prefixWithDir(fileName),
-            'print(\'Wow, such fren, very noyce.\')',
-          )
+          await fs.writeFile(prefixWithDir(fileName), 'print(\'Wow, such fren, very noyce.\')')
         })
 
         await assert.doesNotReject(fs.access(join(dirPath, fileName)))