Remove last vowel

Problems/Remove-The-Last-Vowel/README.md

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+# Remove-The-Last-Vowel
+
+Write a function that removes the last vowel from each word in a sentence.
+
+A vowel is one of: `a, e, i, o, u` (case-insensitive).
+
+Each word in the sentence should be processed independently, and only the **last vowel** of each word should be removed.
+
+Extra challenge (TypeScript/JavaScript):
+Try to implement the solution as a **one-liner**, meaning the function should contain only a `return` statement using method chaining.
+
+## Documentation
+
+### Solution Idea
+
+The sentence is first split into an array of words. Each word is then processed individually.
+
+For every word, create a new variable that will store the modified version of that word.  
+Then iterate through the word from **right to left**, checking each character.
+
+- If the character is **not a vowel**, add it to the new word.
+- If the character **is a vowel**, check whether the new word currently matches the original word up to that position.
+  - If it matches, it means that no vowel has been removed yet, so we **skip this vowel** (this removes the last vowel).
+  - If it does not match, a vowel has already been removed earlier, so we **add the vowel** to the new word.
+
+After processing the whole word, continue with the next word in the array.
+
+Finally, join the modified words back together into a sentence and return the result.
+
+---
+
+### [Implementation](./solver.ts)
+
+First, the sentence is split at each space `" "` to get an array of words.  
+Then we use `map` to process each word individually.
+
+For each word, we split it into characters. To keep the number of methods small, we use `[...str]` to convert the word into an array of characters.
+
+Next, we process this array using `reduceRight`.  
+We could also reverse the array and use `reduce`, but `reduceRight` saves us that extra step.
+
+Inside the `reduceRight` function, we check whether the substring of the original word up to the current index matches the value that is currently being built (`current + previous`). If it matches, it means that **no vowel has been removed yet**.
+
+- If the current character is a vowel, we skip it by returning only the previous value.
+- If it is not a vowel, we return `current + previous`.
+
+If the substring does **not** match anymore, it means a vowel has already been removed earlier, so we simply return `current + previous`.
+
+After `reduceRight` finishes, we have the word without its last vowel.
+
+Once the `map` function has processed all words, we join the array back into a sentence using a space `" "` and return the result.
+
+---
+
+### Information's
+
+This problem comes from the newsletter [Sloth Bytes](https://slothbytes.beehiiv.com).
+[Post](https://slothbytes.beehiiv.com/p/5-things-tutorials-never-teach) from January 07, 2026.

Problems/Remove-The-Last-Vowel/remove-the-last-vowel.test.ts

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+import { describe, expect, it } from "vitest";
+import removeLastVowel from "./solver";
+
+describe("Removes the last vowel for each word in each sentence", () => {
+	it("should return: 'Keybord'", () => {
+		expect(removeLastVowel("Keyboard")).toEqual("Keybord");
+	});
+
+	it("should return: 'Thos wh dar t fal miserbly cn achiev gretly.'", () => {
+		expect(removeLastVowel("Those who dare to fail miserably can achieve greatly.")).toEqual(
+			"Thos wh dar t fal miserbly cn achiev gretly."
+		);
+	});
+
+	it("should return: 'Lov s  serios mentl diseas'", () => {
+		expect(removeLastVowel("Love is a serious mental disease.")).toEqual("Lov s  serios mentl diseas.");
+	});
+
+	it("should return: 'Gt bsy livng r gt bsy dyng'", () => {
+		expect(removeLastVowel("Get busy living or get busy dying.")).toEqual("Gt bsy livng r gt bsy dyng.");
+	});
+
+	it("should return: 'f yo wnt t liv  hppy lif, ti t t  gol, nt t peopl.'", () => {
+		expect(removeLastVowel("If you want to live a happy life, tie it to a goal, not to people.")).toEqual(
+			"f yo wnt t liv  hppy lif, ti t t  gol, nt t peopl."
+		);
+	});
+});

Problems/Remove-The-Last-Vowel/solver.ts

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+/** biome-ignore-all lint/complexity/useIndexOf: Can't use here, searching in an array*/
+
+const vowels: readonly string[] = ["a", "e", "i", "o", "u"];
+
+export default function removeLastVowel(text: string): string {
+	return text
+		.split(" ")
+		.map((str) =>
+			[...str].reduceRight(
+				(preVal, curVal, curI) =>
+					str.substring(curI) === curVal + preVal && vowels.includes(curVal.toLowerCase()) ? preVal : curVal + preVal,
+				""
+			)
+		)
+		.join(" ");
+}

README.md

@@ -8,9 +8,9 @@ This repository is about solving coding-problems. It contains famous (or not tha
 
 ## Problems
 
-Solved: **22 problems**
+Solved: **23 problems**
 
-🟢 Easy: 16  
+🟢 Easy: 17  
 🟠 Medium: 5  
 🔴 Hard: 1
 
@@ -38,6 +38,7 @@ Solved: **22 problems**
 | [Reach Exit](./Problems/Reach-Exit/README.md)                                           | 🟢 Easy    |
 | [One Two Skip a Few](./Problems/One-Two-Skip-A-Few/README.md)                           | 🟢 Easy    |
 | [Day number of year](./Problems/Day-Number-Of-Year/README.md)                           | 🟢 Easy    |
+| [Remove the last vowel](./Problems/Remove-The-Last-Vowel/README.md)                     | 🟢 Easy    |
 
 <!-- PROBLEMS_END -->