Shabina

src/arrays.js

@@ -1,62 +1,50 @@
 const getNthElement = (index, array) => {
-  // your code here
+  return array[index % array.length];
 };
 
-const arrayToCSVString = array => {
-  // your code here
-};
+const arrayToCSVString = array => array.toString();
 
-const csvStringToArray = string => {
-  // your code here
-};
+const csvStringToArray = string => string.split(",");
 
 const addToArray = (element, array) => {
-  // your code here
+  array.push(element);
 };
 
-const addToArray2 = (element, array) => {
-  // your code here
-};
+const addToArray2 = (element, array) => array.concat(element);
 
-const removeNthElement = (index, array) => {
-  // your code here
-};
+const removeNthElement = (index, array) => array.splice(index, 1);
 
-const numbersToStrings = numbers => {
-  // your code here
-};
+const numbersToStrings = numbers => numbers.map(String);
 
-const uppercaseWordsInArray = strings => {
-  // your code here
-};
+const uppercaseWordsInArray = strings => strings.map(a => a.toUpperCase());
 
-const reverseWordsInArray = strings => {
-  // your code here
-};
+const reverseWordsInArray = strings =>
+  strings.map(word => {
+    return word
+      .split("")
+      .reverse()
+      .join("");
+  });
 
-const onlyEven = numbers => {
-  // your code here
-};
+const onlyEven = numbers => numbers.filter(number => number % 2 === 0);
 
-const removeNthElement2 = (index, array) => {
-  // your code here
-};
+const removeNthElement2 = (index, array) =>
+  array.reduce((result, elem, i) => {
+    if (i !== index) result.push(elem);
+    return result;
+  }, []);
 
-const elementsStartingWithAVowel = strings => {
-  // your code here
-};
+const elementsStartingWithAVowel = strings =>
+  strings.filter(str => /^[aeiouAEIOU]/i.test(str));
 
-const removeSpaces = string => {
-  // your code here
-};
+const removeSpaces = string => string.replace(/\s/g, "");
 
-const sumNumbers = numbers => {
-  // your code here
-};
+const sumNumbers = numbers => numbers.reduce((a, b) => a + b);
 
-const sortByLastLetter = strings => {
-  // your code here
-};
+const sortByLastLetter = strings =>
+  strings.sort(
+    (a, b) => a.charCodeAt(a.length - 1) - b.charCodeAt(b.length - 1)
+  );
 
 module.exports = {
   getNthElement,

src/booleans.js

@@ -1,62 +1,36 @@
-const negate = a => {
-  // your code here
-};
+const negate = a => !a;
 
-const both = (a, b) => {
-  // your code here
-};
+const both = (a, b) => a && b;
 
-const either = (a, b) => {
-  // your code here
-};
+const either = (a, b) => a || b;
 
-const none = (a, b) => {
-  // your code here
-};
+const none = (a, b) => !a && !b;
 
 const one = (a, b) => {
-  // your code here
+  if (a && !b) return true;
+  if (!a && b) return true;
+  return false;
 };
 
-const truthiness = a => {
-  // your code here
-};
+const truthiness = a => Boolean(a);
 
-const isEqual = (a, b) => {
-  // your code here
-};
+const isEqual = (a, b) => a === b;
 
-const isGreaterThan = (a, b) => {
-  // your code here
-};
+const isGreaterThan = (a, b) => a > b;
 
-const isLessThanOrEqualTo = (a, b) => {
-  // your code here
-};
+const isLessThanOrEqualTo = (a, b) => a <= b;
 
-const isOdd = a => {
-  // your code here
-};
+const isOdd = a => !(a % 2 === 0);
 
-const isEven = a => {
-  // your code here
-};
+const isEven = a => a % 2 === 0;
 
-const isSquare = a => {
-  // your code here
-};
+const isSquare = a => Math.sqrt(a) % 1 === 0;
 
-const startsWith = (char, string) => {
-  // your code here
-};
+const startsWith = (char, string) => string.startsWith(char);
 
-const containsVowels = string => {
-  // your code here
-};
+const containsVowels = string => Boolean(string.match(/[aeiou]/gi));
 
-const isLowerCase = string => {
-  // your code here
-};
+const isLowerCase = string => string === string.toLowerCase();
 
 module.exports = {
   negate,

src/numbers.js

@@ -1,46 +1,24 @@
-const add = (a, b) => {
-  // your code here
-};
+const add = (a, b) => a + b;
 
-const subtract = (a, b) => {
-  // your code here
-};
+const subtract = (a, b) => a - b;
 
-const multiply = (a, b) => {
-  // your code here
-};
+const multiply = (a, b) => a * b;
 
-const divide = (a, b) => {
-  // your code here
-};
+const divide = (a, b) => a / b;
 
-const power = (a, b) => {
-  // your code here
-};
+const power = (a, b) => a ** b;
 
-const round = a => {
-  // your code here
-};
+const round = a => Math.round(a);
 
-const roundUp = a => {
-  // your code here
-};
+const roundUp = a => Math.ceil(a);
 
-const roundDown = a => {
-  // your code here
-};
+const roundDown = a => Math.floor(a);
 
-const absolute = a => {
-  // your code here
-};
+const absolute = a => Math.abs(a);
 
-const quotient = (a, b) => {
-  // your code here
-};
+const quotient = (a, b) => Math.trunc(a / b);
 
-const remainder = (a, b) => {
-  // your code here
-};
+const remainder = (a, b) => a % b;
 
 module.exports = {
   add,

src/objects.js

@@ -1,41 +1,39 @@
 const createPerson = (name, age) => {
-  // your code here
+  return {
+    name,
+    age
+  };
 };
 
-const getName = object => {
-  // your code here
-};
+const getName = object => object.name;
 
-const getProperty = (property, object) => {
-  // your code here
-};
+const getProperty = (property, object) => object[property];
 
-const hasProperty = (property, object) => {
-  // your code here
-};
+const hasProperty = (property, object) => property in object;
 
-const isOver65 = person => {
-  // your code here
-};
+const isOver65 = person => person.age > 65;
 
-const getAges = people => {
-  // your code here
-};
+const getAges = people => people.map(person => person.age);
 
-const findByName = (name, people) => {
-  // your code here
-};
+const findByName = (name, people) =>
+  people.filter(person => person.name === name)[0];
 
-const findHondas = cars => {
-  // your code here
-};
+const findHondas = cars => cars.filter(car => car.manufacturer === "Honda");
 
 const averageAge = people => {
-  // your code here
+  const ages = people.map(person => person.age);
+  const average = ages.reduce((a, b) => a + b);
+  return average / ages.length;
 };
 
 const createTalkingPerson = (name, age) => {
-  // your code here
+  const person = {
+    name,
+    age,
+    introduce: personname =>
+      `Hi ${personname}, my name is ${name} and I am ${age}!`
+  };
+  return person;
 };
 
 module.exports = {

src/strings.js

@@ -1,26 +1,14 @@
-const sayHello = string => {
-  // your code here
-};
+const sayHello = string => `Hello, ${string}!`;
 
-const uppercase = string => {
-  // your code here
-};
+const uppercase = string => string.toUpperCase();
 
-const lowercase = string => {
-  // your code here
-};
+const lowercase = string => string.toLowerCase();
 
-const countCharacters = string => {
-  // your code here
-};
+const countCharacters = string => string.length;
 
-const firstCharacter = string => {
-  // your code here
-};
+const firstCharacter = string => string.charAt(0);
 
-const firstCharacters = (string, n) => {
-  // your code here
-};
+const firstCharacters = (string, n) => string.substring(0, n);
 
 module.exports = {
   sayHello,