diff --git a/js/tests/happiness-manager_test.mjs b/js/tests/happiness-manager_test.mjs
index be03673f..d5b888a9 100644
--- a/js/tests/happiness-manager_test.mjs
+++ b/js/tests/happiness-manager_test.mjs
@@ -11,13 +11,14 @@ export const setup = async ({ path }) => {
 
   await mkdir(tmpPath)
   await mkdir(`${tmpPath}/guests`)
-  const run = async (folder, file) => {
+  const run = async (dir, file) => {
     const output = await exec(
-      `node ${path} ${tmpPath}/${folder} ${tmpPath}/${file}`,
-    )
-    const fileContent = await readFile(`${tmpPath}/${file}`, 'utf8').catch(
-      (err) => (err.code === 'ENOENT' ? 'output file not found' : err),
+      `node ${path} ${tmpPath}/${dir} ${tmpPath}/${file}`,
     )
+    const fileContent = await readFile(
+      `${tmpPath}/${file}`,
+      'utf8',
+    ).catch(err => (err.code === 'ENOENT' ? 'output file not found' : err))
 
     return {
       data:
@@ -27,18 +28,18 @@ export const setup = async ({ path }) => {
       stdout: output.stdout.trim(),
     }
   }
-  const resetAnswersIn = async ({ folder }) => {
-    const dir = await readdir(`${tmpPath}/${folder}`)
-    await Promise.all(dir.map((file) => rm(`${tmpPath}/${folder}/${file}`)))
+  const resetAnswersIn = async ({ dir }) => {
+    const dir = await readdir(`${tmpPath}/${dir}`)
+    await Promise.all(dir.map(file => rm(`${tmpPath}/${dir}/${file}`)))
   }
   const createAnswers = (nb, elem) => [...Array(nb).keys()].map(() => elem)
-  const setAnswersIn = async ({ answers, folder }) => {
-    await resetAnswersIn({ folder })
+  const setAnswersIn = async ({ answers, dir }) => {
+    await resetAnswersIn({ dir })
     await Promise.all(
       answers.map(
         async (content, idx) =>
           await writeFile(
-            `${tmpPath}/${folder}/${idx}.json`,
+            `${tmpPath}/${dir}/${idx}.json`,
             JSON.stringify(content, null, '\t'),
             'utf8',
           ),
@@ -53,7 +54,7 @@ tests.push(async ({ eq, ctx }) => {
   // test with no vips (no {answer: yes})
   // no file should be created, a special message should appear in console
   const answers = ctx.createAnswers(2, { answer: 'no' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { stdout, data } = await ctx.run('guests', 'happy-list.json')
   return eq(
@@ -66,7 +67,7 @@ tests.push(async ({ eq, ctx }) => {
   // test when vips answer { food: 'carnivores' }
   // should create a list with burgers and potatoes
   const answers = ctx.createAnswers(2, { answer: 'yes', food: 'carnivore' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-carn-list.json')
   return eq(data, { burgers: 2, potatoes: 2 })
@@ -79,7 +80,7 @@ tests.push(async ({ eq, ctx }) => {
     { answer: 'no', food: 'fish' },
     ...ctx.createAnswers(3, { answer: 'yes', food: 'fish' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-fish-list.json')
   return eq(data, { potatoes: 3, sardines: 3 })
@@ -92,7 +93,7 @@ tests.push(async ({ eq, ctx }) => {
     { answer: 'no', food: 'everything' },
     ...ctx.createAnswers(3, { answer: 'yes', food: 'everything' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-omni-list.json')
   return eq(data, { potatoes: 3, kebabs: 3 })
@@ -105,7 +106,7 @@ tests.push(async ({ eq, ctx }) => {
     { answer: 'no', drink: 'beer' },
     ...ctx.createAnswers(1, { answer: 'yes', drink: 'beer' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-beer-list.json')
   return eq(data, { potatoes: 1, '6-packs-beers': 1 })
@@ -118,7 +119,7 @@ tests.push(async ({ eq, ctx }) => {
     { answer: 'no', drink: 'beer' },
     ...ctx.createAnswers(6, { answer: 'yes', drink: 'beer' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-beer-pack-list.json')
   return eq(data, { potatoes: 6, '6-packs-beers': 1 })
@@ -131,7 +132,7 @@ tests.push(async ({ eq, ctx }) => {
     ...ctx.createAnswers(3, { answer: 'no', drink: 'wine' }),
     ...ctx.createAnswers(5, { answer: 'yes', drink: 'wine' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-wine-list.json')
   return eq(data, { potatoes: 5, 'wine-bottles': 2 })
@@ -141,7 +142,7 @@ tests.push(async ({ eq, ctx }) => {
   // test when vips answer { drink: 'wine' }
   // should create a list with wine-bottles and potatoes
   const answers = ctx.createAnswers(8, { answer: 'yes', drink: 'wine' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-wine-bottle-list.json')
   return eq(data, { potatoes: 8, 'wine-bottles': 2 })
@@ -154,7 +155,7 @@ tests.push(async ({ eq, ctx }) => {
     ...ctx.createAnswers(2, { answer: 'no', drink: 'water' }),
     ...ctx.createAnswers(2, { answer: 'yes', drink: 'water' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-water-list.json')
   return eq(data, { potatoes: 2, 'water-bottles': 1 })
@@ -164,7 +165,7 @@ tests.push(async ({ eq, ctx }) => {
   // test when vips answer { drink: 'water' }
   // should create a list with water-bottles and potatoes
   const answers = ctx.createAnswers(7, { answer: 'yes', drink: 'water' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-water-bottle-list.json')
   return eq(data, { potatoes: 7, 'water-bottles': 2 })
@@ -177,7 +178,7 @@ tests.push(async ({ eq, ctx }) => {
     ...ctx.createAnswers(8, { answer: 'no', drink: 'soft' }),
     ...ctx.createAnswers(12, { answer: 'yes', drink: 'soft' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-soft-list.json')
   return eq(data, { potatoes: 12, 'soft-bottles': 3 })
@@ -187,7 +188,7 @@ tests.push(async ({ eq, ctx }) => {
   // test when vips answer { drink: 'soft' }
   // should create a list with soft-bottles and potatoes
   const answers = ctx.createAnswers(13, { answer: 'yes', drink: 'soft' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-soft-bottle-list.json')
   return eq(data, { potatoes: 13, 'soft-bottles': 4 })
@@ -202,7 +203,7 @@ tests.push(async ({ eq, ctx }) => {
     ...ctx.createAnswers(2, { answer: 'no', food: 'vegan' }),
     ...ctx.createAnswers(4, { answer: 'yes', food: 'vegan' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-vegan-list.json')
   return eq(data, {
@@ -218,7 +219,7 @@ tests.push(async ({ eq, ctx }) => {
   // test when vips answer { food: 'vegan' }
   // should create a list with eggplants, mushrooms, hummus, courgettes and potatoes
   const answers = ctx.createAnswers(6, { answer: 'yes', food: 'vegan' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-vegan-list.json')
   return eq(data, {
@@ -238,7 +239,7 @@ tests.push(async ({ eq, ctx }) => {
     ...ctx.createAnswers(2, { answer: 'no', food: 'veggie' }),
     ...ctx.createAnswers(4, { answer: 'yes', food: 'veggie' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-veggie-list.json')
   return eq(data, {
@@ -254,7 +255,7 @@ tests.push(async ({ eq, ctx }) => {
   // test when vips answer { food: 'veggie' }
   // should create a list with eggplants, mushrooms, hummus, courgettes and potatoes
   const answers = ctx.createAnswers(6, { answer: 'yes', food: 'veggie' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-veggie-list.json')
   return eq(data, {
@@ -274,7 +275,7 @@ tests.push(async ({ eq, ctx }) => {
     ...ctx.createAnswers(4, { answer: 'yes', food: 'vegan' }),
     ...ctx.createAnswers(2, { answer: 'yes', food: 'veggie' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-vegg-list.json')
   return eq(data, {
@@ -293,7 +294,7 @@ tests.push(async ({ eq, ctx }) => {
     ...ctx.createAnswers(6, { answer: 'yes', food: 'vegan' }),
     ...ctx.createAnswers(1, { answer: 'yes', food: 'veggie' }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'happy-vegg-list.json')
   return eq(data, {
@@ -314,7 +315,7 @@ tests.push(async ({ eq, ctx }) => {
     JSON.stringify({ candies: 2000 }),
   )
   const answers = ctx.createAnswers(1, { answer: 'yes', food: 'vegan' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'old-happy-list.json')
   return eq(data, {
@@ -335,7 +336,7 @@ tests.push(async ({ eq, ctx }) => {
     JSON.stringify({ candies: 2000, potatoes: 32 }),
   )
   const answers = ctx.createAnswers(1, { answer: 'yes', food: 'vegan' })
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'old-happy-list.json')
   return eq(data, {
@@ -372,7 +373,7 @@ tests.push(async ({ eq, ctx }) => {
       drink: 'beer',
     }),
   ]
-  await ctx.setAnswersIn({ folder: 'guests', answers })
+  await ctx.setAnswersIn({ dir: 'guests', answers })
 
   const { data } = await ctx.run('guests', 'party.json')
   return eq(data, {
diff --git a/js/tests/tell-me-how-many_test.mjs b/js/tests/tell-me-how-many_test.mjs
index 2e8cfb28..c53e7345 100644
--- a/js/tests/tell-me-how-many_test.mjs
+++ b/js/tests/tell-me-how-many_test.mjs
@@ -19,31 +19,31 @@ export const setup = async ({ path }) => {
 
     return { stdout: stdout.trim() }
   }
-  const createXFilesIn = async ({ numberOfFiles, folderPath }) => {
+  const createXFilesIn = async ({ numberOfFiles, dirPath }) => {
     for (let i = 0; i < numberOfFiles; i++) {
-      await writeFile(`${folderPath}/${i}.txt`, '', 'utf8')
+      await writeFile(`${dirPath}/${i}.txt`, '', 'utf8')
     }
   }
-  await createXFilesIn({ numberOfFiles: randomFilesNumber, folderPath: dir })
+  await createXFilesIn({ numberOfFiles: randomFilesNumber, dirPath: dir })
 
   return { randomFilesNumber, tmpPath: dir, run, createXFilesIn }
 }
 
 tests.push(async ({ path, eq, ctx, between }) => {
   const numberOfFiles = between(5, 13)
-  const folderName = `tell-me-how-many-${numberOfFiles}`
-  const folderPath = join(ctx.tmpPath, `../${folderName}`)
-  await mkdir(folderPath)
-  await ctx.createXFilesIn({ folderPath, numberOfFiles })
+  const dirName = `tell-me-how-many-${numberOfFiles}`
+  const dirPath = join(ctx.tmpPath, `../${dirName}`)
+  await mkdir(dirPath)
+  await ctx.createXFilesIn({ dirPath, numberOfFiles })
 
-  const { stdout } = await ctx.run(`../${folderName}`)
+  const { stdout } = await ctx.run(`../${dirName}`)
   return eq(Number(stdout), numberOfFiles)
 })
 
 tests.push(async ({ path, eq, ctx }) => {
-  // will execute the script in a folder named `tell-me-how-many`
+  // will execute the script in a directory named `tell-me-how-many`
   // '../tell-me-how-many' in the argument passed
-  // `tell-me-how-many` folder has a random file number
+  // `tell-me-how-many` directory has a random file number
   const { stdout } = await ctx.run('../tell-me-how-many')
   return eq(Number(stdout), ctx.randomFilesNumber)
 })
@@ -55,7 +55,7 @@ tests.push(async ({ path, eq, ctx }) => {
 })
 
 tests.push(async ({ path, eq, ctx }) => {
-  // will execute the script with `tell-me-how-many` folder's absolute path as argument
+  // will execute the script with `tell-me-how-many` directory's absolute path as argument
   const { stdout } = await ctx.run(ctx.tmpPath)
   return eq(Number(stdout), ctx.randomFilesNumber)
 })
diff --git a/js/tests/tell-me-vip_test.mjs b/js/tests/tell-me-vip_test.mjs
index 4f3778ee..535bf805 100644
--- a/js/tests/tell-me-vip_test.mjs
+++ b/js/tests/tell-me-vip_test.mjs
@@ -12,10 +12,10 @@ export const setup = async ({ path }) => {
 
   await mkdir(`${dir}/guests`, { recursive: true })
 
-  const createFilesIn = ({ files, folderPath }) =>
+  const createFilesIn = ({ files, dirPath }) =>
     Promise.all(
       files.map(([fileName, content]) =>
-        writeFile(`${folderPath}/${fileName}`, JSON.stringify(content)),
+        writeFile(`${dirPath}/${fileName}`, JSON.stringify(content)),
       ),
     )
 
@@ -31,12 +31,12 @@ export const setup = async ({ path }) => {
 }
 
 tests.push(async ({ randStr, eq, ctx }) => {
-  // test when no answers in the folder
-  const folderName = `guests-${randStr()}`
-  const folderPath = join(ctx.tmpPath, folderName)
-  await mkdir(folderPath)
+  // test when no answers in the dir
+  const dirName = `guests-${randStr()}`
+  const dirPath = join(ctx.tmpPath, dirName)
+  await mkdir(dirPath)
 
-  const { data } = await ctx.run(folderName)
+  const { data } = await ctx.run(dirName)
   return eq('', data)
 })
 
@@ -49,12 +49,12 @@ tests.push(async ({ randStr, eq, ctx }) => {
     ['Heath_Denton.json', { answer: 'no' }],
     ['Lilith_Hamilton.json', { answer: 'no' }],
   ]
-  const folderName = `guests-${randStr()}`
-  const folderPath = join(ctx.tmpPath, folderName)
-  await mkdir(folderPath)
-  await ctx.createFilesIn({ folderPath, files })
+  const dirName = `guests-${randStr()}`
+  const dirPath = join(ctx.tmpPath, dirName)
+  await mkdir(dirPath)
+  await ctx.createFilesIn({ dirPath, files })
 
-  const { data } = await ctx.run(folderName)
+  const { data } = await ctx.run(dirName)
   return eq('', data)
 })
 
@@ -68,12 +68,12 @@ tests.push(async ({ randStr, eq, ctx }) => {
     ['Lilith_Hamilton.json', { answer: 'yes' }],
     [`${random}_Random.json`, { answer: 'yes' }],
   ]
-  const folderName = `guests-${randStr()}`
-  const folderPath = join(ctx.tmpPath, folderName)
-  await mkdir(folderPath)
-  await ctx.createFilesIn({ folderPath, files })
+  const dirName = `guests-${randStr()}`
+  const dirPath = join(ctx.tmpPath, dirName)
+  await mkdir(dirPath)
+  await ctx.createFilesIn({ dirPath, files })
 
-  const { data } = await ctx.run(folderName)
+  const { data } = await ctx.run(dirName)
   return eq(
     [
       `1. Ballard Ubaid`,
diff --git a/js/tests/tell-me-who_test.mjs b/js/tests/tell-me-who_test.mjs
index 1c129658..2fea4652 100644
--- a/js/tests/tell-me-who_test.mjs
+++ b/js/tests/tell-me-who_test.mjs
@@ -11,10 +11,10 @@ export const setup = async ({ path }) => {
   const dir = `${tmpdir()}/tell-me-who`
   await mkdir(dir)
 
-  const createFilesIn = async ({ fileNames, folderPath }) =>
+  const createFilesIn = async ({ fileNames, dirPath }) =>
     await Promise.all(
       fileNames.map(
-        async (fileName) => await writeFile(`${folderPath}/${fileName}`, ''),
+        async (fileName) => await writeFile(`${dirPath}/${fileName}`, ''),
       ),
     )
 
@@ -37,12 +37,12 @@ tests.push(async ({ eq, ctx, randStr }) => {
     'Heath_Denton.json',
     `${random}_Hamilton.json`,
   ]
-  const folderName = `them-${randStr()}`
-  const folderPath = join(ctx.tmpPath, folderName)
-  await mkdir(folderPath)
-  await ctx.createFilesIn({ folderPath, fileNames })
+  const dirName = `them-${randStr()}`
+  const dirPath = join(ctx.tmpPath, dirName)
+  await mkdir(dirPath)
+  await ctx.createFilesIn({ dirPath, fileNames })
 
-  const { stdout } = await ctx.run(folderName)
+  const { stdout } = await ctx.run(dirName)
   return eq(
     [
       `1. Ballard Ubaid`,
diff --git a/subjects/happiness-manager/README.md b/subjects/happiness-manager/README.md
index a03dcf6f..21358bfc 100644
--- a/subjects/happiness-manager/README.md
+++ b/subjects/happiness-manager/README.md
@@ -14,7 +14,7 @@ who wants to eat what and integrate that in your barbecue's shopping list!
 
 The script must:
 
-- Take a folder as first argument (the `guest` folder)
+- Take a directory as first argument (the `guest` directory)
 - Take a file `.json` as second argument:
   - If the file already exists, it will add the informations to it.
   - If it doesn't, the script must handle the creation of the file.
diff --git a/subjects/tell-me-how-many/README.md b/subjects/tell-me-how-many/README.md
index 9705deca..93ea5103 100644
--- a/subjects/tell-me-how-many/README.md
+++ b/subjects/tell-me-how-many/README.md
@@ -2,20 +2,24 @@
 
 ### Instructions
 
-Your very favorite person's birthday is coming soon. So you've decided to organise a very special party 🥳🪅🎤
+Your very favorite person's birthday is coming soon. So you've decided to
+organise a very special party 🥳🪅🎤
 
 Invitations has been sent for a while...
 
-Good news: answers are back!
-Psst: Sorry buddy, we didn't count it, you've been too generous. But we saved every one of them as a file in a special folder for you. Have fun!
+Good news: answers are back! Psst: Sorry buddy, we didn't count it, you've been
+too generous. But we saved every one of them as a file in a special directory for
+you. Have fun!
 
 Create a `tell-me-how-many.mjs` script that:
-- Take a relative or absolute folder path as argument from the command line.
+
+- Take a relative or absolute directory path as argument from the command line.
 - Read this directory path.
-- Get the number of entries in this folder.
+- Get the number of entries in this directory.
 - Print the result in console.
 
-If there is no argument passed, the script must execute itself in the current directory
+If there is no argument passed, the script must execute itself in the current
+directory
 
 ### Notions
 
@@ -23,6 +27,7 @@ If there is no argument passed, the script must execute itself in the current di
 
 ### Provided files
 
-Download [`guests.zip`](https://assets.01-edu.org/tell-me-how-many/guests.zip) to have at your disposal the `guests` folder containing the files to count in your script. You must save it in your `tell-me-how-many` exercise folder to test your script on it.
-
-
+Download [`guests.zip`](https://assets.01-edu.org/tell-me-how-many/guests.zip)
+to have at your disposal the `guests` directory containing the files to count in
+your script. You must save it in your `tell-me-how-many` exercise directory to test
+your script on it.
diff --git a/subjects/tell-me-who/README.md b/subjects/tell-me-who/README.md
index 390873b0..a14a5ecb 100644
--- a/subjects/tell-me-who/README.md
+++ b/subjects/tell-me-who/README.md
@@ -2,16 +2,17 @@
 
 ### Instructions
 
-Create a `tell-me-who.mjs` script that takes your folder path as an argument
+Create a `tell-me-who.mjs` script that takes your directory path as an argument
 and print the names of the guests that answered to your invitation in the
 console.
 
-The output must print one guest per line, in ascending alphabetic
-order, and formated as following: `Number. Lastname Firstname` (starting from 1).
+The output must print one guest per line, in ascending alphabetic order, and
+formated as following: `Number. Lastname Firstname` (starting from 1).
 
 ### Notions
 
 - [Node file system: `readdir`](https://nodejs.org/api/fs.html#fs_fspromises_readdir_path_options)
+- [`Promise.all()` method](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise/all)
 - [`Array.prototype.map()` method](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/map)
 - [`String.prototype.split()` method](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/split)
 - [`Array.prototype.join()` method](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/join)