dedupe function created & test cases created

Author: mervereis

Sprint-1/implement/dedupe.js

@@ -1 +1,6 @@
-function dedupe() {}
+function dedupe(arr) {
+  if (arr.length === 0) return [];
+  return [...new Set(arr)];
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,27 +1,50 @@
-const dedupe = require("./dedupe.js");
-/*
-Dedupe Array
+const dedupe = require("./dedupe");
 
-📖 Dedupe means **deduplicate**
+describe("dedupe", () => {
+  // Given an empty array
+  // When passed to the dedupe function
+  // Then it should return an empty array
+  test.todo("given an empty array, it returns an empty array");
+  test("given an empty array, it returns an empty array", () => {
+    const result = dedupe([]);
+    expect(result).toEqual([]);
+  });
 
-In this kata, you will need to deduplicate the elements of an array
+  // Given an array with no duplicates
+  // When passed to the dedupe function
+  // Then it should return a copy of the original array
+  test("given an array with no duplicates, it returns a copy of the original array", () => {
+    const input = [1, 2, 3, 4];
+    const result = dedupe(input);
 
-E.g. dedupe(['a','a','a','b','b','c']) target output: ['a','b','c']
-E.g. dedupe([5, 1, 1, 2, 3, 2, 5, 8]) target output: [5, 1, 2, 3, 8]
-E.g. dedupe([1, 2, 1]) target output: [1, 2]
-*/
+    expect(result).toEqual([1, 2, 3, 4]);
+    expect(result).not.toBe(input); // should be a new copy
+  });
 
-// Acceptance Criteria:
+  // Given an array with strings
+  // When passed to the dedupe function
+  // Then it should remove duplicates preserving first occurrence
+  test("removes duplicate strings preserving first occurrence", () => {
+    const input = ["a", "a", "a", "b", "b", "c"];
+    const result = dedupe(input);
 
-// Given an empty array
-// When passed to the dedupe function
-// Then it should return an empty array
-test.todo("given an empty array, it returns an empty array");
+    expect(result).toEqual(["a", "b", "c"]);
+  });
 
-// Given an array with no duplicates
-// When passed to the dedupe function
-// Then it should return a copy of the original array
+  // Given an array with numbers
+  // When passed to the dedupe function
+  // Then it should remove the duplicate values, preserving the first occurence of each element
+  test("removes duplicate numbers preserving first occurrence", () => {
+    const input = [5, 1, 1, 2, 3, 2, 5, 8];
+    const result = dedupe(input);
 
-// Given an array with strings or numbers
-// When passed to the dedupe function
-// Then it should remove the duplicate values, preserving the first occurence of each element
+    expect(result).toEqual([5, 1, 2, 3, 8]);
+  });
+
+  test("removes duplicates in mixed order", () => {
+    const input = [1, 2, 1];
+    const result = dedupe(input);
+
+    expect(result).toEqual([1, 2]);
+  });
+});