Combining Arrays Without Duplicates

Author: Tittoh

README.md

@@ -17,4 +17,5 @@ Once inside, run the command below:
 8. Search and Replace
 9. Anagram
 10. Pig-latin
-11. Chunk Array
+11. Chunk Array
+12. Combining Arrays Without Duplicates

src/mergeArray/index.js

@@ -0,0 +1,12 @@
+// pick a solution and insert here to run the test.
+
+function mergeArrays(...arrays) {
+    let jointArray = []
+    
+    arrays.forEach(array => {
+        jointArray = [...jointArray, ...array]
+    });
+    return Array.from(new Set([...jointArray]))
+}
+
+module.exports =  mergeArrays;

src/mergeArray/solutions.js

@@ -0,0 +1,59 @@
+// USING A SET
+function mergeArrays(...arrays) {
+
+    let jointArray = []
+    
+    arrays.forEach(array => {
+        jointArray = [...jointArray, ...array]
+    });
+
+    return [...new Set([...jointArray])]
+
+}
+
+// USING ARRAY.FROM() WITH SET
+
+function mergeArrays(...arrays) {
+    let jointArray = []
+    
+    arrays.forEach(array => {
+        jointArray = [...jointArray, ...array]
+    });
+    return Array.from(new Set([...jointArray]))
+}
+
+// USING .FILTER()
+
+function mergeArrays(...arrays) {
+
+    let jointArray = []
+    
+    arrays.forEach(array => {
+        jointArray = [...jointArray, ...array]
+    })
+
+    const uniqueArray = jointArray.filter((item,index) => jointArray.indexOf(item) === index)
+
+    return uniqueArray
+}
+
+// USING .REDUCE()
+
+function mergeArrays(...arrays) {
+
+    let jointArray = []
+    
+    arrays.forEach(array => {
+        jointArray = [...jointArray, ...array]
+    })
+
+    const uniqueArray = jointArray.reduce((newArray, item) =>{
+        if (newArray.includes(item)){
+            return newArray
+        } else {
+            return [...newArray, item]
+        }
+    }, [])
+
+    return uniqueArray
+}

src/mergeArray/test.js

@@ -0,0 +1,13 @@
+const mergeArrays = require('./index');
+
+test('mergeArrays is a function', () => {
+  expect(typeof mergeArrays).toEqual('function');
+});
+
+test('Combines 5 arrays of numbers without dubplicates', () => {
+  expect(mergeArrays([1,2],[2,3],[3,4],[4,5])).toEqual([1,2,3,4,5]);
+});
+
+test('Combines 3 arrays of strings without dubplicates', () => {
+  expect(mergeArrays(['a','b','z'],['m','n','a'],['z','y'])).toEqual(['a','b', 'z', 'm', 'n', 'y']);
+});