London | 26-ITP-May | Eyob Zeray | Sprint 1 | course work

Sprint-1/fix/median.js

@@ -1,14 +1,30 @@
 // Fix this implementation
 // Start by running the tests for this function
-// If you're in the Sprint-1 directory, you can run `npm test -- fix` to run the tests in the fix directory
+// If you're in the Sprint-1 directory, you can run npm test -- fix to run the tests in the fix directory
 
 // Hint: Please consider scenarios when 'list' doesn't have numbers (the function is expected to return null)
 // or 'list' has mixed values (the function is expected to sort only numbers).
 
 function calculateMedian(list) {
-  const middleIndex = Math.floor(list.length / 2);
-  const median = list.splice(middleIndex, 1)[0];
-  return median;
+  if (!Array.isArray(list)) {
+    return null;
+  }
+
+  const numbers = list.filter((item) => typeof item === "number" && !Number.isNaN(item));
+
+  if (numbers.length === 0) {
+    return null;
+  }
+
+  numbers.sort((a, b) => a - b);
+
+  const middleIndex = Math.floor(numbers.length / 2);
+
+  if (numbers.length % 2 === 0) {
+    return (numbers[middleIndex - 1] + numbers[middleIndex]) / 2;
+  }
+
+  return numbers[middleIndex];
 }
 
 module.exports = calculateMedian;

Sprint-1/implement/dedupe.js

@@ -1 +1,13 @@
-function dedupe() {}
+function dedupe(elements) {
+  const seen = [];
+
+  elements.forEach((item) => {
+    if (!seen.includes(item)) {
+      seen.push(item);
+    }
+  });
+
+  return seen;
+}
+
+module.exports = dedupe;

Sprint-1/implement/dedupe.test.js

@@ -1,28 +1,16 @@
 const dedupe = require("./dedupe.js");
-/*
-Dedupe Array
+test("given an empty array, it returns an empty array", () => {
+  expect(dedupe([])).toEqual([]);
+});
 
-📖 Dedupe means **deduplicate**
+test("given an array with no duplicates, returns a copy of the original array", () => {
+  expect(dedupe([1, 2, 3])).toEqual([1, 2, 3]);
+});
 
-In this kata, you will need to deduplicate the elements of an array
+test("given an array of strings, removes duplicates preserving first occurrence", () => {
+  expect(dedupe(["a", "a", "a", "b", "b", "c"])).toEqual(["a", "b", "c"]);
+});
 
-E.g. dedupe(['a','a','a','b','b','c']) returns ['a','b','c']
-E.g. dedupe([5, 1, 1, 2, 3, 2, 5, 8]) returns [5, 1, 2, 3, 8]
-E.g. dedupe([1, 2, 1]) returns [1, 2]
-*/
-
-// Acceptance Criteria:
-
-// 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");
-
-// 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 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 numbers, removes duplicates preserving first occurrence", () => {
+  expect(dedupe([5, 1, 1, 2, 3, 2, 5, 8])).toEqual([5, 1, 2, 3, 8]);
+});

Sprint-1/implement/max.js

@@ -1,4 +1,7 @@
-function findMax(elements) {
+function findMax(list) {
+  const numbers = list.filter((item) => typeof item === "number" && !Number.isNaN(item));
+
+  return numbers.reduce((max, current) => (current > max ? current : max), -Infinity);
 }
 
-module.exports = findMax;
+module.exports = findMax;

Sprint-1/implement/max.test.js

@@ -1,43 +1,29 @@
-/* Find the maximum element of an array of numbers
-
-In this kata, you will need to implement a function that find the largest numerical element of an array.
-
-E.g. max([30, 50, 10, 40]), target output: 50
-E.g. max(['hey', 10, 'hi', 60, 10]), target output: 60 (sum ignores any non-numerical elements)
-
-You should implement this function in max.js, and add tests for it in this file.
-
-We have set things up already so that this file can see your function from the other file.
-*/
-
 const findMax = require("./max.js");
 
-// Given an empty array
-// 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([])).toEqual(-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([42])).toEqual(42);
+});
 
-// 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 positive and negative numbers, returns the largest overall", () => {
+  expect(findMax([-5, 10, -20, 3])).toEqual(10);
+});
 
-// 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 only negative numbers, returns the closest to zero", () => {
+  expect(findMax([-5, -1, -10])).toEqual(-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", () => {
+  expect(findMax([1.5, 2.75, 2.5])).toEqual(2.75);
+});
 
-// Given an array with non-number values
-// When passed to the max function
-// Then it should return the max and ignore non-numeric values
+test("given an array with non-number values, ignores them and returns the max", () => {
+  expect(findMax(["hey", 10, "hi", 60, 10])).toEqual(60);
+});
 
-// Given an array with only non-number values
-// When passed to the max function
-// Then it should return the least surprising value given how it behaves for all other inputs
+test("given an array with only non-number values, returns -Infinity", () => {
+  expect(findMax(["hey", "hi", "hello"])).toEqual(-Infinity);
+});

Sprint-1/implement/sum.js

@@ -1,4 +1,7 @@
 function sum(elements) {
+  const numbers = elements.filter((item) => typeof item === "number" && !Number.isNaN(item));
+
+  return numbers.reduce((total, current) => total + current, 0);
 }
 
 module.exports = sum;

Sprint-1/implement/sum.test.js

@@ -1,36 +1,25 @@
-/* Sum the numbers in an array
-
-In this kata, you will need to implement a function that sums the numerical elements of an array
-
-E.g. sum([10, 20, 30]), target output: 60
-E.g. sum(['hey', 10, 'hi', 60, 10]), target output: 80 (ignore any non-numerical elements)
-*/
-
 const sum = require("./sum.js");
 
-// Acceptance Criteria:
-
-// 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([])).toEqual(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, returns that number", () => {
+  expect(sum([7])).toEqual(7);
+});
 
-// 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 containing negative numbers, returns the correct total sum", () => {
+  expect(sum([10, -5, 3])).toEqual(8);
+});
 
-// 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 numbers, returns the correct total sum", () => {
+  expect(sum([1.5, 2.25, 0.25])).toEqual(4);
+});
 
-// Given an array containing non-number values
-// When passed to the sum function
-// Then it should ignore the non-numerical values and return the sum of the numerical elements
+test("given an array containing non-number values, ignores them and sums the rest", () => {
+  expect(sum(["hey", 10, "hi", 60, 10])).toEqual(80);
+});
 
-// Given an array with only non-number values
-// When passed to the sum function
-// Then it should return the least surprising value given how it behaves for all other inputs
+test("given an array with only non-number values, returns 0", () => {
+  expect(sum(["hey", "hi", "hello"])).toEqual(0);
+});

Sprint-1/refactor/includes.js

@@ -1,8 +1,7 @@
 // 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];
+  for (const element of list) {
     if (element === target) {
       return true;
     }