fix(curriculum): adding explanation for indexOf in music player project (#53024)

2026-03-05 14:00:41 -05:00 · 2024-01-09 05:54:17 -08:00
parent 6a8ae4102c
commit 9c4e9d2ee8
51 changed files with 835 additions and 163 deletions
--- a/curriculum/challenges/_meta/learn-basic-string-and-array-methods-by-building-a-music-player/meta.json
+++ b/curriculum/challenges/_meta/learn-basic-string-and-array-methods-by-building-a-music-player/meta.json
@@ -157,196 +157,200 @@
      "title": "Step 36"
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+      "id": "65572e5aaf022790fb4a81b1",
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+      "id": "655737cd004591b0271d6826",
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+      "id": "65573a97c59ddbbf028ca95e",
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+      "id": "65573d0abe4d38cd6fa13f44",
      "title": "Step 81"
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-      "id": "655b4bbff1dbf66cb2ed4dac",
+      "id": "655b49333d9f265bc1512152",
      "title": "Step 82"
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+      "id": "655b4bbff1dbf66cb2ed4dac",
      "title": "Step 83"
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    {
-      "id": "655b4dad1d38ff7cdd65cbfe",
+      "id": "655b4c8f636d9675953a0388",
      "title": "Step 84"
+    },
+    {
+      "id": "655b4dad1d38ff7cdd65cbfe",
+      "title": "Step 85"
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  "helpCategory": "JavaScript"
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6552385244ccf89b77d6b332.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6552385244ccf89b77d6b332.md
@@ -1,8 +1,8 @@
 ---
 id: 6552385244ccf89b77d6b332
-title: Step 37
+title: Step 38
 challengeType: 0
-dashedName: step-37
+dashedName: step-38
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655243068222c2c1166b90b0.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655243068222c2c1166b90b0.md
@@ -1,8 +1,8 @@
 ---
 id: 655243068222c2c1166b90b0
-title: Step 38
+title: Step 39
 challengeType: 0
-dashedName: step-38
+dashedName: step-39
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655476e1ff522252fdcce5e4.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655476e1ff522252fdcce5e4.md
@@ -1,8 +1,8 @@
 ---
 id: 655476e1ff522252fdcce5e4
-title: Step 39
+title: Step 40
 challengeType: 0
-dashedName: step-39
+dashedName: step-40
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655479aa3e1e0360ae38b7a6.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655479aa3e1e0360ae38b7a6.md
@@ -1,8 +1,8 @@
 ---
 id: 655479aa3e1e0360ae38b7a6
-title: Step 40
+title: Step 41
 challengeType: 0
-dashedName: step-40
+dashedName: step-41
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65547ee197840478a1b95f4b.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65547ee197840478a1b95f4b.md
@@ -1,8 +1,8 @@
 ---
 id: 65547ee197840478a1b95f4b
-title: Step 41
+title: Step 42
 challengeType: 0
-dashedName: step-41
+dashedName: step-42
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6554815fe2472f8bfdab7642.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6554815fe2472f8bfdab7642.md
@@ -1,8 +1,8 @@
 ---
 id: 6554815fe2472f8bfdab7642
-title: Step 42
+title: Step 43
 challengeType: 0
-dashedName: step-42
+dashedName: step-43
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655482742cc5499726e3f347.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655482742cc5499726e3f347.md
@@ -1,8 +1,8 @@
 ---
 id: 655482742cc5499726e3f347
-title: Step 43
+title: Step 44
 challengeType: 0
-dashedName: step-43
+dashedName: step-44
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655483ebf0096ba02b2c3d4c.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655483ebf0096ba02b2c3d4c.md
@@ -1,8 +1,8 @@
 ---
 id: 655483ebf0096ba02b2c3d4c
-title: Step 44
+title: Step 45
 challengeType: 0
-dashedName: step-44
+dashedName: step-45
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655485321913feabbc5f00f8.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655485321913feabbc5f00f8.md
@@ -1,8 +1,8 @@
 ---
 id: 655485321913feabbc5f00f8
-title: Step 45
+title: Step 46
 challengeType: 0
-dashedName: step-45
+dashedName: step-46
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6554860ea4dfbab2f4786fc8.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6554860ea4dfbab2f4786fc8.md
@@ -1,8 +1,8 @@
 ---
 id: 6554860ea4dfbab2f4786fc8
-title: Step 46
+title: Step 47
 challengeType: 0
-dashedName: step-46
+dashedName: step-47
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655487f686aabfc2a10ba887.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655487f686aabfc2a10ba887.md
@@ -7,36 +7,22 @@ dashedName: step-36

 # --description--

-Before you start working on playing the next and previous song, you need to get the index of each song in the `songs` property of `userData`. Remember this is where you spread in the songs.
+Before you start working on playing the next and previous song, you need to get the index of each song in the `songs` property of `userData`. 

-Use an arrow syntax to create a `getCurrentSongIndex` function. Then, using implicit return, use the `indexOf()` method on `userData?.songs`, and pass in `userData.currentSong`.
-
-Calling this function will get you the index of each song.
+Start by creating an arrow function called `getCurrentSongIndex`.

 # --hints--

-You should use `const` to create a `getCurrentSongIndex` function.
+You should have a `getCurrentSongIndex` function.

 ```js
-assert.match(code, /const\s+getCurrentSongIndex\s*/)
+assert.isFunction(getCurrentSongIndex);
 ```

 Your `getCurrentSongIndex` function should use arrow syntax.

 ```js
-assert.match(code, /const\s+getCurrentSongIndex\s*=\s*\(\)\s*=>\s*/)
-```
-
-Your `getCurrentSongIndex` function should implicitly use the `indexOf()` method on `userData?.songs`. 
-
-```js
-assert.match(code, /const\s+getCurrentSongIndex\s*=\s*\(\)\s*=>\s*userData\?\.songs\.indexOf\(/)
-```
-
-You should pass in `userData.currentSong` into the `indexOf()`.
-
-```js
-assert.match(code, /const\s+getCurrentSongIndex\s*=\s*\(\)\s*=>\s*userData\?\.songs\.indexOf\(userData\.currentSong\);?/)
+assert.match(code, /(let|const)\s+getCurrentSongIndex\s*=\s*\(\)\s*=>\s*{\s*}\s*/);
 ```

 # --seed--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65548f747a4cdafd186948d1.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65548f747a4cdafd186948d1.md
@@ -1,8 +1,8 @@
 ---
 id: 65548f747a4cdafd186948d1
-title: Step 47
+title: Step 48
 challengeType: 0
-dashedName: step-47
+dashedName: step-48
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655490f55c36900779336988.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655490f55c36900779336988.md
@@ -1,8 +1,8 @@
 ---
 id: 655490f55c36900779336988
-title: Step 48
+title: Step 49
 challengeType: 0
-dashedName: step-48
+dashedName: step-49
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 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655492e6b90c7a198c587943.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655492e6b90c7a198c587943.md
@@ -1,8 +1,8 @@
 ---
 id: 655492e6b90c7a198c587943
-title: Step 50
+title: Step 51
 challengeType: 0
-dashedName: step-50
+dashedName: step-51
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655494d5a15d6a2567e1ea60.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655494d5a15d6a2567e1ea60.md
@@ -1,8 +1,8 @@
 ---
 id: 655494d5a15d6a2567e1ea60
-title: Step 51
+title: Step 52
 challengeType: 0
-dashedName: step-51
+dashedName: step-52
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 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655495a6bd96e42bc3baa795.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655495a6bd96e42bc3baa795.md
@@ -1,8 +1,8 @@
 ---
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-title: Step 52
+title: Step 53
 challengeType: 0
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+dashedName: step-53
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 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d17af9ff06a14d399f6d.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d17af9ff06a14d399f6d.md
@@ -1,8 +1,8 @@
 ---
 id: 6555d17af9ff06a14d399f6d
-title: Step 53
+title: Step 54
 challengeType: 0
-dashedName: step-53
+dashedName: step-54
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d458687cb3b357834df9.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d458687cb3b357834df9.md
@@ -1,8 +1,8 @@
 ---
 id: 6555d458687cb3b357834df9
-title: Step 54
+title: Step 55
 challengeType: 0
-dashedName: step-54
+dashedName: step-55
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 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d729c9bfd7c3195f1948.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d729c9bfd7c3195f1948.md
@@ -1,8 +1,8 @@
 ---
 id: 6555d729c9bfd7c3195f1948
-title: Step 55
+title: Step 56
 challengeType: 0
-dashedName: step-55
+dashedName: step-56
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d7e384056dc9c581fadf.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d7e384056dc9c581fadf.md
@@ -1,8 +1,8 @@
 ---
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-title: Step 56
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 challengeType: 0
-dashedName: step-56
+dashedName: step-57
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d8faed60b9d3e4a6cefb.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555d8faed60b9d3e4a6cefb.md
@@ -1,8 +1,8 @@
 ---
 id: 6555d8faed60b9d3e4a6cefb
-title: Step 57
+title: Step 58
 challengeType: 0
-dashedName: step-57
+dashedName: step-58
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555dd138e70cae6b546966d.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555dd138e70cae6b546966d.md
@@ -1,8 +1,8 @@
 ---
 id: 6555dd138e70cae6b546966d
-title: Step 58
+title: Step 59
 challengeType: 0
-dashedName: step-58
+dashedName: step-59
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555de565387a2efe90a6ccc.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555de565387a2efe90a6ccc.md
@@ -1,8 +1,8 @@
 ---
 id: 6555de565387a2efe90a6ccc
-title: Step 59
+title: Step 60
 challengeType: 0
-dashedName: step-59
+dashedName: step-60
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e04aeb225bfbae237344.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e04aeb225bfbae237344.md
@@ -1,8 +1,8 @@
 ---
 id: 6555e04aeb225bfbae237344
-title: Step 60
+title: Step 61
 challengeType: 0
-dashedName: step-60
+dashedName: step-61
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e0bfe4d69904410f7cd3.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e0bfe4d69904410f7cd3.md
@@ -1,8 +1,8 @@
 ---
 id: 6555e0bfe4d69904410f7cd3
-title: Step 61
+title: Step 62
 challengeType: 0
-dashedName: step-61
+dashedName: step-62
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e39a5f4c6f138c7d9405.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e39a5f4c6f138c7d9405.md
@@ -1,8 +1,8 @@
 ---
 id: 6555e39a5f4c6f138c7d9405
-title: Step 62
+title: Step 63
 challengeType: 0
-dashedName: step-62
+dashedName: step-63
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e57d3e6d9d221c4735be.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e57d3e6d9d221c4735be.md
@@ -1,8 +1,8 @@
 ---
 id: 6555e57d3e6d9d221c4735be
-title: Step 63
+title: Step 64
 challengeType: 0
-dashedName: step-63
+dashedName: step-64
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e6cec786da2aadc11ea0.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e6cec786da2aadc11ea0.md
@@ -1,8 +1,8 @@
 ---
 id: 6555e6cec786da2aadc11ea0
-title: Step 64
+title: Step 65
 challengeType: 0
-dashedName: step-64
+dashedName: step-65
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e7acdbae972d3e8e0f5b.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e7acdbae972d3e8e0f5b.md
@@ -1,8 +1,8 @@
 ---
 id: 6555e7acdbae972d3e8e0f5b
-title: Step 65
+title: Step 66
 challengeType: 0
-dashedName: step-65
+dashedName: step-66
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e9197bf1d7416bdd76e0.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555e9197bf1d7416bdd76e0.md
@@ -1,8 +1,8 @@
 ---
 id: 6555e9197bf1d7416bdd76e0
-title: Step 66
+title: Step 67
 challengeType: 0
-dashedName: step-66
+dashedName: step-67
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555ebf07ec610585a626f72.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6555ebf07ec610585a626f72.md
@@ -1,8 +1,8 @@
 ---
 id: 6555ebf07ec610585a626f72
-title: Step 67
+title: Step 68
 challengeType: 0
-dashedName: step-67
+dashedName: step-68
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65571e742fbf4532d8f98e90.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65571e742fbf4532d8f98e90.md
@@ -1,8 +1,8 @@
 ---
 id: 65571e742fbf4532d8f98e90
-title: Step 68
+title: Step 69
 challengeType: 0
-dashedName: step-68
+dashedName: step-69
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655720534347cb3f31cdfb3d.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655720534347cb3f31cdfb3d.md
@@ -1,8 +1,8 @@
 ---
 id: 655720534347cb3f31cdfb3d
-title: Step 69
+title: Step 70
 challengeType: 0
-dashedName: step-69
+dashedName: step-70
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65572399a8e16d50bc2c1ff3.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65572399a8e16d50bc2c1ff3.md
@@ -1,8 +1,8 @@
 ---
 id: 65572399a8e16d50bc2c1ff3
-title: Step 70
+title: Step 71
 challengeType: 0
-dashedName: step-70
+dashedName: step-71
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655724bac464795a0ad91082.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655724bac464795a0ad91082.md
@@ -1,8 +1,8 @@
 ---
 id: 655724bac464795a0ad91082
-title: Step 72
+title: Step 73
 challengeType: 0
-dashedName: step-72
+dashedName: step-73
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655727b2e1e49d6adf584442.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655727b2e1e49d6adf584442.md
@@ -1,8 +1,8 @@
 ---
 id: 655727b2e1e49d6adf584442
-title: Step 73
+title: Step 74
 challengeType: 0
-dashedName: step-73
+dashedName: step-74
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655729e68e49b277a6b448bd.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655729e68e49b277a6b448bd.md
@@ -1,8 +1,8 @@
 ---
 id: 655729e68e49b277a6b448bd
-title: Step 75
+title: Step 76
 challengeType: 0
-dashedName: step-75
+dashedName: step-76
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65572bb34a7e488224b937fc.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65572bb34a7e488224b937fc.md
@@ -1,8 +1,8 @@
 ---
 id: 65572bb34a7e488224b937fc
-title: Step 76
+title: Step 77
 challengeType: 0
-dashedName: step-76
+dashedName: step-77
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65572e5aaf022790fb4a81b1.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65572e5aaf022790fb4a81b1.md
@@ -1,8 +1,8 @@
 ---
 id: 65572e5aaf022790fb4a81b1
-title: Step 77
+title: Step 78
 challengeType: 0
-dashedName: step-77
+dashedName: step-78
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655737cd004591b0271d6826.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655737cd004591b0271d6826.md
@@ -1,8 +1,8 @@
 ---
 id: 655737cd004591b0271d6826
-title: Step 78
+title: Step 79
 challengeType: 0
-dashedName: step-78
+dashedName: step-79
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65573a97c59ddbbf028ca95e.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65573a97c59ddbbf028ca95e.md
@@ -1,8 +1,8 @@
 ---
 id: 65573a97c59ddbbf028ca95e
-title: Step 79
+title: Step 80
 challengeType: 0
-dashedName: step-79
+dashedName: step-80
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65573d0abe4d38cd6fa13f44.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65573d0abe4d38cd6fa13f44.md
@@ -1,8 +1,8 @@
 ---
 id: 65573d0abe4d38cd6fa13f44
-title: Step 80
+title: Step 81
 challengeType: 0
-dashedName: step-80
+dashedName: step-81
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6557421eb6a7a0f0500e3106.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/6557421eb6a7a0f0500e3106.md
@@ -1,8 +1,8 @@
 ---
 id: 6557421eb6a7a0f0500e3106
-title: Step 71
+title: Step 72
 challengeType: 0
-dashedName: step-71
+dashedName: step-72
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b49333d9f265bc1512152.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b49333d9f265bc1512152.md
@@ -1,8 +1,8 @@
 ---
 id: 655b49333d9f265bc1512152
-title: Step 81
+title: Step 82
 challengeType: 0
-dashedName: step-81
+dashedName: step-82
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b4bbff1dbf66cb2ed4dac.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b4bbff1dbf66cb2ed4dac.md
@@ -1,8 +1,8 @@
 ---
 id: 655b4bbff1dbf66cb2ed4dac
-title: Step 82
+title: Step 83
 challengeType: 0
-dashedName: step-82
+dashedName: step-83
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b4c8f636d9675953a0388.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b4c8f636d9675953a0388.md
@@ -1,8 +1,8 @@
 ---
 id: 655b4c8f636d9675953a0388
-title: Step 83
+title: Step 84
 challengeType: 0
-dashedName: step-83
+dashedName: step-84
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b4dad1d38ff7cdd65cbfe.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/655b4dad1d38ff7cdd65cbfe.md
@@ -1,8 +1,8 @@
 ---
 id: 655b4dad1d38ff7cdd65cbfe
-title: Step 84
+title: Step 85
 challengeType: 0
-dashedName: step-84
+dashedName: step-85
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65671421254eeb489875cdd8.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65671421254eeb489875cdd8.md
@@ -1,8 +1,8 @@
 ---
 id: 65671421254eeb489875cdd8
-title: Step 49
+title: Step 50
 challengeType: 0
-dashedName: step-49
+dashedName: step-50
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65672adafbaa37a6cef886f7.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/65672adafbaa37a6cef886f7.md
@@ -1,8 +1,8 @@
 ---
 id: 65672adafbaa37a6cef886f7
-title: Step 74
+title: Step 75
 challengeType: 0
-dashedName: step-74
+dashedName: step-75
 ---

 # --description--
--- a/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/659b0093d7db5a1a1122b7bd.md
+++ b/curriculum/challenges/english/15-javascript-algorithms-and-data-structures-22/learn-basic-string-and-array-methods-by-building-a-music-player/659b0093d7db5a1a1122b7bd.md
@@ -0,0 +1,682 @@
+---
+id: 659b0093d7db5a1a1122b7bd
+title: Step 37
+challengeType: 0
+dashedName: step-37
+---
+
+# --description--
+
+To get the index for the current song, you can use the <dfn>indexOf()</dfn> method. The `indexOf()` array method returns the first index at which a given element can be found in the array, or `-1` if the element is not present.
+
+```js
+const animals = ["dog", "cat", "horse"];
+animals.indexOf("cat") // 1
+```
+
+Inside your `getCurrentSongIndex` function, return `userData?.songs.indexOf()`. For the `indexOf()` argument, set it to `userData.currentSong`.
+
+# --hints--
+
+You should return `userData?.songs.indexOf()` inside your `getCurrentSongIndex` function.
+
+```js
+assert.match(code, /const\s+getCurrentSongIndex\s*=\s*\(\)\s*=>(\s*userData\?\.songs\.indexOf\()|(\s*{\s*return?\s+userData\?\.songs\.indexOf\()/)
+```
+
+You should pass in `userData.currentSong` into the `indexOf()` method.
+
+```js
+assert.match(code, /const\s+getCurrentSongIndex\s*=\s*\(\)\s*=>(\s*userData\?\.songs\.indexOf\(userData\.currentSong\);?)|(\s*{\s*return\s+userData\?\.songs\.indexOf\(userData\.currentSong\);?)/)
+```
+
+# --seed--
+
+## --seed-contents--
+
+```html
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <link
+      href="https://fonts.googleapis.com/css2?family=Roboto+Mono&display=swap"
+      rel="stylesheet"
+    />
+    <link
+      href="https://fonts.googleapis.com/css2?family=Lato&family=Roboto+Mono&display=swap"
+      rel="stylesheet"
+    />
+    <link rel="stylesheet" href="styles.css" />
+    <title>
+      Learn Basic String and Array Methods by Building a Music Player App
+    </title>
+  </head>
+
+  <body>
+    <div class="container">
+      <div class="player">
+        <div class="player-bar">
+          <div class="parallel-lines">
+            <div></div>
+            <div></div>
+          </div>
+          <h1 class="fcc-title">freeCodeCamp</h1>
+          <div class="parallel-lines">
+            <div></div>
+            <div></div>
+          </div>
+        </div>
+        <div class="player-content">
+          <div id="player-album-art">
+            <img
+              src="https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/quincy-larson-album-art.jpg"
+              alt="song cover art"
+            />
+          </div>
+          <div class="player-display">
+            <div class="player-display-song-artist">
+              <p id="player-song-title"></p>
+              <p id="player-song-artist"></p>
+            </div>
+            <div class="player-buttons">
+              <button id="previous" class="previous" aria-label="Previous">
+                <svg
+                  width="24"
+                  height="19"
+                  viewBox="0 0 24 19"
+                  fill="none"
+                  xmlns="http://www.w3.org/2000/svg"
+                ><path d="M23.2248 0L7.03964 9.5L23.2248 19L23.2248 0Z" /><rect
+                    width="4.63633"
+                    height="18.5453"
+                    transform="matrix(-1 0 0 1 4.63633 0)"/></svg>
+              </button>
+              <button id="play" class="play" aria-label="Play">
+                <svg
+                  width="17"
+                  height="19"
+                  viewBox="0 0 17 19"
+                  fill="none"
+                  xmlns="http://www.w3.org/2000/svg"
+                > <path d="M0 0L16.1852 9.5L1.88952e-07 19L0 0Z" /></svg>
+              </button>
+              <button id="pause" class="pause" aria-label="Pause">
+                <svg
+                  width="17"
+                  height="19"
+                  viewBox="0 0 17 19"
+                  fill="none"
+                  xmlns="http://www.w3.org/2000/svg"
+                ><path d="M0 6.54013e-07H4.75V19H0V6.54013e-07Z" /> <path d="M11.4 0H16.15V19H11.4V0Z" /></svg>
+              </button>
+              <button id="next" class="next" aria-label="Next">
+                <svg
+                  width="24"
+                  height="19"
+                  viewBox="0 0 24 19"
+                  fill="none"
+                  xmlns="http://www.w3.org/2000/svg"
+                ><path d="M0 0L16.1852 9.5L1.88952e-07 19L0 0Z" /> <rect x="18.5885" width="4.63633" height="18.5453" /></svg>
+              </button>
+              <button id="shuffle" class="shuffle" aria-label="Shuffle">
+                <svg
+                  width="17"
+                  height="14"
+                  viewBox="0 0 17 14"
+                  fill="none"
+                  xmlns="http://www.w3.org/2000/svg"
+                ><path
+                    fill-rule="evenodd"
+                    clip-rule="evenodd"
+                    d="M12.2127 0L17 2.9219L12.0759 5.60686L12.1321 3.30594C11.9081 3.30997 11.7043 3.3165 11.528 3.326C11.3777 3.3341 11.2523 3.34411 11.1542 3.35578C11.1053 3.3616 11.0661 3.36749 11.036 3.37309C11.0211 3.37587 11.0095 3.37835 11.001 3.38041C10.9967 3.38143 10.9936 3.38227 10.9913 3.38289C10.989 3.38352 10.988 3.38385 10.9881 3.38382C10.9266 3.40381 10.7572 3.5014 10.4637 3.73265C10.1895 3.94866 9.85452 4.24234 9.47614 4.59282C8.81462 5.20556 8.03912 5.97461 7.25609 6.76752C8.03912 7.56043 8.81462 8.32948 9.47614 8.94223C9.85452 9.29271 10.1895 9.58639 10.4637 9.80239C10.7572 10.0336 10.9266 10.1312 10.9881 10.1512C10.988 10.1512 10.989 10.1515 10.9913 10.1522C10.9936 10.1528 10.9967 10.1536 11.001 10.1546C11.0095 10.1567 11.0211 10.1592 11.036 10.162C11.0661 10.1676 11.1053 10.1734 11.1542 10.1793C11.2523 10.1909 11.3777 10.2009 11.528 10.209C11.7043 10.2185 11.9081 10.2251 12.1321 10.2291L12.0759 7.92819L17 10.6131L12.2127 13.535L12.1558 11.2011C11.9071 11.197 11.677 11.1899 11.4757 11.1791C11.175 11.1629 10.8757 11.1361 10.6878 11.0751C10.4405 10.9947 10.1465 10.7892 9.86244 10.5654C9.55904 10.3263 9.20251 10.0129 8.81601 9.6549C8.14192 9.03051 7.35822 8.2533 6.57518 7.46052C6.2731 7.76927 5.9736 8.07675 5.68453 8.37353C5.24051 8.8294 4.82109 9.26001 4.45467 9.63114C4.10458 9.98574 3.79502 10.2941 3.54834 10.5285C3.42516 10.6455 3.31437 10.7473 3.22005 10.8285C3.13287 10.9035 3.03686 10.9812 2.94938 11.0324C2.46156 11.3178 1.79381 11.3751 1.32395 11.3812C1.07514 11.3845 0.852462 11.3732 0.692065 11.3611C0.611577 11.3551 0.546037 11.3488 0.499864 11.344C0.476761 11.3415 0.458455 11.3394 0.445496 11.3379L0.43012 11.336L0.425557 11.3355L0.423542 11.3352C0.423448 11.3352 0.423143 11.3352 0.485767 10.8535L0.423542 11.3352C0.157529 11.3006 -0.0304782 11.0569 0.00410824 10.7909C0.0386807 10.525 0.282182 10.3374 0.548069 10.3718C0.548087 10.3718 0.548051 10.3718 0.548069 10.3718L0.549944 10.372L0.559616 10.3732C0.568682 10.3743 0.582871 10.3759 0.60165 10.3779C0.639243 10.3818 0.695017 10.3872 0.764728 10.3924C0.90473 10.4029 1.09799 10.4127 1.31133 10.4099C1.76571 10.404 2.20705 10.3412 2.4587 10.194C2.45847 10.1941 2.4583 10.1942 2.4587 10.194C2.46075 10.1926 2.47161 10.1855 2.49271 10.1693C2.51674 10.1508 2.54777 10.1254 2.58634 10.0922C2.66358 10.0258 2.7615 9.93612 2.87917 9.82431C3.11419 9.60097 3.41488 9.30164 3.76339 8.94864C4.1317 8.57559 4.54478 8.15147 4.98424 7.70025C5.27761 7.39904 5.58273 7.08575 5.89415 6.76752C5.58272 6.44928 5.27759 6.13598 4.98421 5.83476C4.54476 5.38355 4.1317 4.95944 3.76339 4.5864C3.41488 4.2334 3.11419 3.93407 2.87917 3.71074C2.7615 3.59892 2.66358 3.50929 2.58634 3.44281C2.54777 3.40961 2.51674 3.38425 2.49271 3.36577C2.4716 3.34954 2.46099 3.34258 2.45894 3.34123C2.45868 3.34108 2.45853 3.34096 2.45894 3.34123C2.2073 3.19405 1.76572 3.13106 1.31133 3.12515C1.09799 3.12238 0.90473 3.13211 0.764728 3.14261C0.695017 3.14784 0.639243 3.15321 0.60165 3.15717C0.582871 3.15915 0.568682 3.16077 0.559616 3.16184L0.549944 3.16301L0.548391 3.1632C0.282436 3.1977 0.0386882 3.01013 0.00410824 2.74417C-0.0304782 2.47816 0.15713 2.23447 0.423143 2.19989L0.485767 2.68154C0.423143 2.19989 0.423048 2.1999 0.423143 2.19989L0.425557 2.19958L0.43012 2.199L0.445496 2.19714C0.458455 2.19561 0.476761 2.19352 0.499864 2.19109C0.546037 2.18622 0.611577 2.17995 0.692065 2.17391C0.852462 2.16188 1.07514 2.15058 1.32395 2.15381C1.79381 2.15992 2.46156 2.21726 2.94938 2.50267C3.03686 2.55385 3.13287 2.63152 3.22005 2.70655C3.31437 2.78773 3.42516 2.8895 3.54834 3.00655C3.79502 3.24097 4.10458 3.54931 4.45467 3.9039C4.82109 4.27504 5.24052 4.70565 5.68455 5.16153C5.97361 5.4583 6.2731 5.76578 6.57518 6.07452C7.35822 5.28174 8.14192 4.50454 8.81601 3.88014C9.20251 3.52214 9.55904 3.20872 9.86244 2.96964C10.1465 2.74581 10.4405 2.54035 10.6878 2.45997C10.8757 2.39892 11.175 2.37219 11.4757 2.35598C11.677 2.34514 11.9071 2.33807 12.1558 2.33396L12.2127 0Z"
+                  /></svg>
+              </button>
+            </div>
+          </div>
+        </div>
+      </div>
+      <div class="playlist">
+        <div class="playlist-bar">
+          <div class="parallel-lines">
+            <div></div>
+            <div></div>
+          </div>
+          <h2 class="playlist-title" id="playlist">Playlist</h2>
+          <div class="parallel-lines">
+            <div></div>
+            <div></div>
+          </div>
+        </div>
+        <ul id="playlist-songs"></ul>
+      </div>
+    </div>
+    <script src="script.js"></script>
+  </body>
+</html>
+```
+
+```css
+:root {
+  /* colors */
+  --primary-color: #dfdfe2;
+  --secondary-color: #ffffff;
+  --app-background-color: #4d4d62;
+  --background-color: #1b1b32;
+  --foreground-color: #3b3b4f;
+  --highlight-color: #f1be32;
+
+  /* font sizes */
+  --root-font-size: 16px;
+  font-size: var(--root-font-size);
+
+  /* font-families */
+  --font-headline: "Roboto Mono", monospace;
+  --font-family: "Lato", sans-serif;
+}
+
+*,
+*::after,
+*::before {
+  box-sizing: border-box;
+}
+
+body {
+  background-color: var(--app-background-color);
+  color: var(--primary-color);
+  font-family: var(--font-family);
+}
+
+h1 {
+  font-size: 1.125rem;
+  line-height: 1.6;
+}
+
+h2 {
+  font-size: var(--root-font-size);
+}
+
+ul {
+  margin: 0;
+}
+
+.container {
+  margin-top: 10px;
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  align-items: center;
+  row-gap: 5px;
+}
+
+.player,
+.playlist {
+  width: 450px;
+  background-color: var(--background-color);
+  border: 3px solid var(--foreground-color);
+}
+
+.player {
+  height: 260px;
+  padding: 10px;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  row-gap: 10px;
+}
+
+.player-bar,
+.playlist-bar {
+  display: flex;
+  justify-content: space-between;
+  align-items: center;
+  padding: 0 5px;
+  width: 100%;
+  height: 30px;
+  background-color: var(--foreground-color);
+}
+
+.parallel-lines {
+  display: flex;
+  flex-wrap: wrap;
+  row-gap: 6px;
+  padding: 0 5px;
+}
+
+.parallel-lines > div {
+  height: 2px;
+  width: 100%;
+  min-width: 75px;
+  background-color: var(--highlight-color);
+}
+
+.fcc-title,
+.playlist-title {
+  color: var(--secondary-color);
+  margin: 0 10px;
+  font-family: var(--font-headline);
+}
+
+.player-content {
+  display: flex;
+  background-color: var(--foreground-color);
+  width: 430px;
+  height: 200px;
+  column-gap: 13px;
+  align-items: center;
+  justify-content: center;
+}
+
+#player-album-art {
+  background-color: var(--secondary-color);
+  border: 6px solid var(--background-color);
+}
+
+#player-album-art img {
+  width: 150px;
+  display: block;
+}
+
+.player-display {
+  display: flex;
+  flex-direction: column;
+  row-gap: 20px;
+  padding: 14px;
+  background-color: var(--background-color);
+  height: 153px;
+  width: 226px;
+}
+
+.player-display-song-artist {
+  height: 80px;
+}
+
+.player-buttons svg {
+  fill: var(--primary-color);
+}
+
+.playing > svg {
+  fill: var(--highlight-color);
+}
+
+.player-buttons {
+  display: flex;
+  justify-content: space-around;
+}
+
+button {
+  background: transparent;
+  border: none;
+  color: var(--primary-color);
+  cursor: pointer;
+  font-size: var(--root-font-size);
+  outline-color: var(--highlight-color);
+  text-align: center;
+}
+
+.playlist-song {
+  outline-color: var(--highlight-color);
+}
+
+.playlist li:not(:last-child) {
+  border-bottom: 1px solid var(--background-color);
+}
+
+button:focus,
+.playlist-song:focus {
+  outline-style: dashed;
+  outline-width: 2px;
+}
+
+/* Playlist */
+.playlist {
+  height: auto;
+  padding: 10px;
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  row-gap: 10px;
+}
+
+#playlist-songs {
+  width: 430px;
+  height: 100%;
+  background-color: var(--foreground-color);
+  display: flex;
+  flex-direction: column;
+  row-gap: 8px;
+  padding: 8px 9px;
+  visibility: visible;
+  justify-content: start;
+  list-style: none;
+}
+
+.playlist-song {
+  display: flex;
+  height: 55px;
+  justify-content: space-between;
+  align-items: center;
+  padding: 5px;
+}
+
+[aria-current="true"] {
+  background-color: var(--background-color);
+}
+
+[aria-current="true"] p {
+  color: var(--highlight-color);
+}
+
+.playlist-song-info {
+  height: 100%;
+  display: flex;
+  flex-direction: row;
+  align-items: center;
+  justify-content: space-around;
+  column-gap: 7px;
+  padding: 5px 0;
+  font-family: var(--font-family);
+}
+
+#player-song-title,
+#player-song-artist {
+  margin: 0;
+}
+
+#player-song-artist {
+  color: var(--highlight-color);
+  font-size: 0.75rem;
+}
+
+#player-song-title {
+  font-size: 1.125rem;
+}
+
+.playlist-song-title {
+  font-size: 0.85rem;
+  width: 241px;
+  text-align: left;
+}
+
+.playlist-song-artist {
+  font-size: 0.725rem;
+  width: 80px;
+}
+
+.playlist-song-duration {
+  font-size: 0.725rem;
+  margin: auto;
+  font-family: var(--font-headline);
+  width: 30px;
+}
+
+.playlist-song-delete {
+  padding: 0;
+  width: 20px;
+  height: 20px;
+}
+
+.playlist-song-delete,
+.playlist-song-delete {
+  fill: var(--foreground-color);
+}
+
+.playlist-song-delete:hover circle,
+.playlist-song-delete:focus circle {
+  fill: #ff0000;
+}
+
+@media (max-width: 700px) {
+  .player,
+  .playlist {
+    width: 300px;
+  }
+
+  .player {
+    height: 340px;
+  }
+
+  #playlist-songs {
+    height: 280px;
+    padding: 5px 6px;
+    overflow-y: scroll;
+    overflow-x: hidden;
+    scrollbar-color: var(--background-color) var(--secondary-color);
+    scrollbar-width: thin;
+  }
+
+  #playlist-songs::-webkit-scrollbar {
+    width: 5px;
+  }
+
+  #playlist-songs::-webkit-scrollbar-track {
+    background: var(--background-color);
+  }
+
+  #playlist-songs::-webkit-scrollbar-thumb {
+    background: var(--secondary-color);
+  }
+
+  h1 {
+    font-size: 0.813rem;
+  }
+
+  h2 {
+    font-size: 0.75rem;
+  }
+
+  .player-bar,
+  .playlist-bar,
+  .player-content,
+  #playlist-songs {
+    width: 280px;
+  }
+
+  .playlist-song {
+    justify-content: space-between;
+  }
+
+  .playlist-song-title {
+    width: 140px;
+  }
+
+  .playlist-song-artist {
+    width: 40px;
+  }
+
+  .playlist-song-duration > button {
+    padding: 0;
+  }
+
+  .player-content {
+    display: inline;
+    position: relative;
+    justify-items: center;
+    height: 100%;
+  }
+
+  #player-album-art {
+    z-index: -100;
+    height: 280px;
+    box-shadow: none;
+    background: #000;
+  }
+
+  #player-album-art img {
+    width: 100%;
+    opacity: 0.6;
+  }
+
+  .player-display-song-artist {
+    padding: 0 10px;
+  }
+
+  .player-display-song-artist > p {
+    white-space: pre-wrap;
+  }
+
+  .player-display {
+    position: absolute;
+    width: 100%;
+    z-index: 1000;
+    background-color: transparent;
+    top: 0;
+    height: 280px;
+    justify-content: space-between;
+    text-align: center;
+  }
+}
+```
+
+```js
+const playlistSongs = document.getElementById("playlist-songs");
+const playButton = document.getElementById("play");
+const pauseButton = document.getElementById("pause");
+const nextButton = document.getElementById("next");
+const previousButton = document.getElementById("previous");
+const shuffleButton = document.getElementById("shuffle");
+
+const allSongs = [
+  {
+    id: 0,
+    title: "Scratching The Surface",
+    artist: "Quincy Larson",
+    duration: "4:25",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/scratching-the-surface.mp3",
+  },
+  {
+    id: 1,
+    title: "Can't Stay Down",
+    artist: "Quincy Larson",
+    duration: "4:15",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/cant-stay-down.mp3",
+  },
+  {
+    id: 2,
+    title: "Still Learning",
+    artist: "Quincy Larson",
+    duration: "3:51",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/still-learning.mp3",
+  },
+  {
+    id: 3,
+    title: "Cruising for a Musing",
+    artist: "Quincy Larson",
+    duration: "3:34",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/cruising-for-a-musing.mp3",
+  },
+  {
+    id: 4,
+    title: "Never Not Favored",
+    artist: "Quincy Larson",
+    duration: "3:35",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/never-not-favored.mp3",
+  },
+  {
+    id: 5,
+    title: "From the Ground Up",
+    artist: "Quincy Larson",
+    duration: "3:12",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/from-the-ground-up.mp3",
+  },
+  {
+    id: 6,
+    title: "Walking on Air",
+    artist: "Quincy Larson",
+    duration: "3:25",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/walking-on-air.mp3",
+  },
+  {
+    id: 7,
+    title: "Can't Stop Me. Can't Even Slow Me Down.",
+    artist: "Quincy Larson",
+    duration: "3:52",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/cant-stop-me-cant-even-slow-me-down.mp3",
+  },
+  {
+    id: 8,
+    title: "The Surest Way Out is Through",
+    artist: "Quincy Larson",
+    duration: "3:10",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/the-surest-way-out-is-through.mp3",
+  },
+  {
+    id: 9,
+    title: "Chasing That Feeling",
+    artist: "Quincy Larson",
+    duration: "2:43",
+    src: "https://s3.amazonaws.com/org.freecodecamp.mp3-player-project/chasing-that-feeling.mp3",
+  },
+];
+
+const audio = new Audio();
+let userData = {
+  songs: [...allSongs],
+  currentSong: null,
+  songCurrentTime: 0,
+};
+
+const playSong = (id) => {
+  const song = userData?.songs.find((song) => song.id === id);
+  audio.src = song.src;
+  audio.title = song.title;
+
+  if (userData?.currentSong === null || userData?.currentSong.id !== song.id) {
+    audio.currentTime = 0;
+  } else {
+    audio.currentTime = userData.songCurrentTime;
+  }
+  userData.currentSong = song;
+  playButton.classList.add("playing");
+
+  audio.play();
+};
+
+const pauseSong = () => {
+  userData.songCurrentTime = audio.currentTime;
+  
+  playButton.classList.remove("playing");
+  audio.pause();
+};
+
+const renderSongs = (array) => {
+  const songsHTML = array
+    .map((song)=> {
+      return `
+      <li id="song-${song.id}" class="playlist-song">
+      <button class="playlist-song-info" onclick="playSong(${song.id})">
+          <span class="playlist-song-title">${song.title}</span>
+          <span class="playlist-song-artist">${song.artist}</span>
+          <span class="playlist-song-duration">${song.duration}</span>
+      </button>
+      <button class="playlist-song-delete" aria-label="Delete ${song.title}">
+          <svg width="20" height="20" viewBox="0 0 16 16" fill="none" xmlns="http://www.w3.org/2000/svg"><circle cx="8" cy="8" r="8" fill="#4d4d62"/>
+          <path fill-rule="evenodd" clip-rule="evenodd" d="M5.32587 5.18571C5.7107 4.90301 6.28333 4.94814 6.60485 5.28651L8 6.75478L9.39515 5.28651C9.71667 4.94814 10.2893 4.90301 10.6741 5.18571C11.059 5.4684 11.1103 5.97188 10.7888 6.31026L9.1832 7.99999L10.7888 9.68974C11.1103 10.0281 11.059 10.5316 10.6741 10.8143C10.2893 11.097 9.71667 11.0519 9.39515 10.7135L8 9.24521L6.60485 10.7135C6.28333 11.0519 5.7107 11.097 5.32587 10.8143C4.94102 10.5316 4.88969 10.0281 5.21121 9.68974L6.8168 7.99999L5.21122 6.31026C4.8897 5.97188 4.94102 5.4684 5.32587 5.18571Z" fill="white"/></svg>
+        </button>
+      </li>
+      `;
+    })
+    .join("");
+
+  playlistSongs.innerHTML = songsHTML;
+};
+
+--fcc-editable-region--
+const getCurrentSongIndex = () => {
+
+}
+--fcc-editable-region--
+
+playButton.addEventListener("click", () => {
+    if (userData?.currentSong === null) {
+    playSong(userData?.songs[0].id);
+  } else {
+    playSong(userData?.currentSong.id);
+  }
+});
+
+pauseButton.addEventListener("click",  pauseSong);
+
+renderSongs(userData?.songs);
+```