London | 26-ITP-Sep | Ebrahim Moqbel | Sprint 1 | course work CYF-1071

Sprint-1/fix/median.js

@@ -6,9 +6,29 @@
 // or contains values that aren't numbers (the function is expected to throw - see the tests).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  // validate the array
+  if (!Array.isArray(list)) {
+    throw new Error("calculateMedian requires an array of numbers");
+  }
+  // Empty array should throw an error
+  if (list.length === 0) {
+    throw new Error("calculateMedian requires a non-empty array");
+  }
+
+  const allNumbers = list.every(
+    (item) => typeof item === "number" && !Number.isNaN(item)
+  );
+  if (!allNumbers) {
+    throw new Error("calculateMedian requires an array of numbers");
+  }
+  const sorted = [...list].sort((a, b) => a - b);
+  const middleIndex = Math.floor(sorted.length / 2);
+
+  if (sorted.length % 2 == 0) {
+    return (sorted[middleIndex - 1] + sorted[middleIndex]) / 2;
+  } else {
+    return sorted[middleIndex];
+  }
 }
 
 module.exports = calculateMedian;

Sprint-1/fix/median.test.js

@@ -47,20 +47,14 @@ describe("calculateMedian", () => {
     expect(calculateMedian([6, -2, 2, 12, 14])).toEqual(6);
   });
 
-  it("doesn't modify the input array [3, 1, 2]", () => {
-    const list = [3, 1, 2];
-    calculateMedian(list);
-    expect(list).toEqual([3, 1, 2]);
-  });
-
-  // There is no median of an empty array, so calculateMedian should throw
+  // There is no median of an empty array, so calculateMedian should throw an error
   it("throws when given an empty array", () => {
     expect(() => calculateMedian([])).toThrow(
       new Error("calculateMedian requires a non-empty array")
     );
   });
 
-  // Input that isn't an array should throw
+  // Input that isn't an array should throw an error
   it("throws when given a string", () => {
     expect(() => calculateMedian("banana")).toThrow(
       new Error("calculateMedian requires an array of numbers")
@@ -91,7 +85,7 @@ describe("calculateMedian", () => {
     );
   });
 
-  // Arrays containing any non-number value should throw, rather than filtering them out
+  // Arrays containing any non-number value should throw an error , rather than filtering them out
   it("throws for an array of strings", () => {
     expect(() => calculateMedian(["ten", "twenty", "thirty"])).toThrow(
       new Error("calculateMedian requires an array of numbers")

Sprint-1/implement/dedupe.js

@@ -1 +1,12 @@
-function dedupe() {}
+function dedupe(arr) {
+    // initialize an empty array 
+    let dedupedArr =[];
+    for( element of arr){
+        if(!dedupedArr.includes(element)){
+            dedupedArr.push(element);
+        }
+
+    }
+    return dedupedArr
+}
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,4 +1,5 @@
 const dedupe = require("./dedupe.js");
+
 /*
 Dedupe Array
 
@@ -16,13 +17,22 @@ E.g. dedupe([1, 2, 1]) returns [1, 2]
 // 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", ()=>{
+    expect(dedupe([])).toEqual([])
+});
 
 // 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, returns a copy of the original array", ()=>{
+    expect(dedupe([3,4,6])).toEqual([3,4,6])
 
+})
 // Given an array of strings or numbers
 // When passed to the dedupe function
 // Then it should return a new array with duplicates removed while preserving the 
 // first occurrence of each element from the original array.
+test('Given an array of strings or numbers, returns a new array with duplicates removed while preserving the first occurrence of each element from the original array',()=>{
+    expect(dedupe(['h',4,'k','h',3,5,4])).toEqual(['h',4,'k',3,5])
+}
+)

Sprint-1/implement/max.js

@@ -1,4 +1,22 @@
 function findMax(elements) {
+  // checking if the input is an array
+  if (!Array.isArray(elements)) {
+    throw new Error("findMax requires an array of numbers");
+  }
+  if (elements.length === 0) {
+    return -Infinity;
+  }
+  const allNumbers = elements.every(
+    (item) => typeof item === "number" && !Number.isNaN(item)
+  );
+  if (!allNumbers) {
+    throw new Error("findMax requires an array of numbers");
+  }
+
+  const sorted = [...elements].sort((a, b) => a - b);
+  const max = sorted[sorted.length - 1];
+
+  return max;
 }
 
 module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -16,28 +16,50 @@ const findMax = require("./max.js");
 // When passed to the max function
 // Then it should return -Infinity
 // Delete this test.todo and replace it with a test.
-test.todo("given an empty array, returns -Infinity");
+test("given an empty array, returns -Infinity", () => {
+  expect(findMax([])).toBe(-Infinity);
+});
 
 // Given an array with one number
 // When passed to the max function
 // Then it should return that number
+test("Given an array with one number, returns that number", () => {
+  expect(findMax([22])).toBe(22);
+});
 
 // Given an array with both positive and negative numbers
 // When passed to the max function
 // Then it should return the largest number overall
-
+test("Given an array with both positive and negative numbers, returns the largest number ", () => {
+  expect(findMax([-3, 6, -9])).toBe(6);
+});
 // Given an array with just negative numbers
 // When passed to the max function
 // Then it should return the closest one to zero
-
+test("Given an array with just negative numbers, returns the closest one to zero", () => {
+  expect(findMax([-3, -4, -1])).toBe(-1);
+});
 // Given an array with decimal numbers
 // When passed to the max function
 // Then it should return the largest decimal number
+test("Given an array with decimal numbers, returns the largest decimal number", () => {
+  expect(findMax([3.5, 4.5, 6.5])).toBe(6.5);
+});
 
 // Given an array containing a value that isn't a number
 // When passed to the max function
 // Then it should throw Error("findMax requires an array of numbers")
+test("throws an error when given a non number value", () => {
+  expect(() => findMax(["3", 5, "undefined", null])).toThrow(
+    new Error("findMax requires an array of numbers")
+  );
+});
 
 // Given something that isn't an array at all, such as "hey", 42 or no argument
 // When passed to the max function
 // Then it should throw Error("findMax requires an array of numbers")
+test("throws an error when given an array with only non-number values", () => {
+  expect(() => findMax(["Holla!", NaN, true])).toThrow(
+    new Error("findMax requires an array of numbers")
+  );
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,24 @@
 function sum(elements) {
+  if (!Array.isArray(elements)) {
+    throw new Error("sum requires an array of numbers");
+  }
+
+  if (elements.length === 0) {
+    return 0;
+  }
+  // every element must be a valid number
+  const allNumbers = elements.every(
+    (item) => typeof item === "number" && !Number.isNaN(item)
+  );
+  if (!allNumbers) {
+    throw new Error("sum requires an array of numbers");
+  }
+
+  let total = 0;
+  for (let i = 0; i < elements.length; i++) {
+    total += elements[i];
+  }
+  return total;
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -13,24 +13,44 @@ const sum = require("./sum.js");
 // Given an empty array
 // When passed to the sum function
 // Then it should return 0
-test.todo("given an empty array, returns 0")
+test("given an empty array, returns 0", () => {
+  expect(sum([])).toBe(0);
+});
 
 // Given an array with just one number
 // When passed to the sum function
 // Then it should return that number
-
+test("Given an array with just one number, return that number", () => {
+  expect(sum([3])).toBe(3);
+});
 // Given an array containing negative numbers
 // When passed to the sum function
 // Then it should still return the correct total sum
+test("Given an array with negative numbers, return the correct total", () => {
+  expect(sum([-2, -4, -1])).toBe(-7);
+});
 
 // Given an array with decimal/float numbers
 // When passed to the sum function
 // Then it should return the correct total sum
+test("Given an array with decimal/float numbers, returns the correct total sum", () => {
+  expect(sum([3.5, 6.1])).toBe(9.6);
+});
 
 // Given an array containing a value that isn't a number
 // When passed to the sum function
 // Then it should throw Error("sum requires an array of numbers")
+test("throws an error when given an array contains a non-number value", () => {
+  expect(() => sum(["4", "Holla", 6, 9, 1])).toThrow(
+    new Error("sum requires an array of numbers")
+  );
+});
 
 // Given something that isn't an array at all, such as "hey", 42 or no argument
 // When passed to the sum function
 // Then it should throw Error("sum requires an array of numbers")
+test("throws an error when given a non array value", () => {
+  expect(() => sum([null, undefined, NaN, true])).toThrow(
+    new Error("sum requires an array of numbers")
+  );
+});

Sprint-1/refactor/includes.js

@@ -1,13 +1,21 @@
 // Refactor the implementation of includes to use a for...of loop
 
-function includes(list, target) {
-  for (let index = 0; index < list.length; index++) {
-    const element = list[index];
-    if (element === target) {
-      return true;
+// function includes(list, target) {
+//   for (let index = 0; index < list.length; index++) {
+//     const element = list[index];
+//     if (element === target) {
+//       return true;
+//     }
+//   }
+//   return false;
+// }
+function includes(list, target){
+  for (element of list){
+    if(element === target){
+      return true
     }
   }
-  return false;
+  return false
 }
 
 module.exports = includes;