Mandatory & Extra(I have a problem with Magic Ball

extra/1-currency-conversion.js

@@ -5,7 +5,9 @@
   Write a function that converts a price to USD (exchange rate is 1.4 $ to £)
 */
 
-function convertToUSD() {}
+function convertToUSD(pound) {
+  return pound * 1.4;
+}
 
 /*
   CURRENCY CONVERSION
@@ -15,7 +17,11 @@ function convertToUSD() {}
   They have also decided that they should add a 1% fee to all foreign transactions, which means you only convert 99% of the £ to BRL.
 */
 
-function convertToBRL() {}
+function convertToBRL(pound) {
+  let fee = pound / 100;
+  let converting = (pound - fee) * 5.7;
+  return Number(converting.toFixed(2));
+}
 
 /* ======= TESTS - DO NOT MODIFY ===== 
 There are some Tests in this file that will help you work out if your code is working.

extra/2-piping.js

@@ -16,26 +16,28 @@
   the final result to the variable goodCode
 */
 
-function add() {
-
+function add(a, b) {
+  return a + b;
 }
 
-function multiply() {
-
+function multiply(a, b) {
+  return a * b;
 }
 
-function format() {
-
+function format(num) {
+  return String("£" + num);
 }
 
 const startingValue = 2;
 
 // Why can this code be seen as bad practice? Comment your answer.
-let badCode =
+let badCode = format(multiply(add(startingValue, 10), 2));
 
 /* BETTER PRACTICE */
+let plusTen = add(10, startingValue);
+let multiplyByTwo = multiply(plusTen, 2);
 
-let goodCode =
+let goodCode = format(multiplyByTwo);
 
 /* ======= TESTS - DO NOT MODIFY ===== 
 There are some Tests in this file that will help you work out if your code is working.

extra/3-magic-8-ball.js

@@ -1,3 +1,7 @@
+// import jest extended matchers
+const jestExtended = require("jest-extended");
+// extend the existing jest class with the jest-extended matchers
+expect.extend(jestExtended);
 /**
 
   Let's peer into the future using a Magic 8 Ball!
@@ -45,10 +49,39 @@
 
 // This should log "The ball has shaken!"
 // and return the answer.
+const answers = [
+  "It is certain.",
+  "It is decidedly so.",
+  "Without a doubt.",
+  "Yes - definitely.",
+  "You may rely on it.",
+  "As I see it, yes.",
+  "Most likely.",
+  "Outlook good.",
+  "Yes.",
+  "Signs point to yes.",
+  "Reply hazy, try again.",
+  "Ask again later.",
+  "Better not tell you now.",
+  "Cannot predict now.",
+  "Concentrate and ask again.",
+  "Don't count on it.",
+  "My reply is no.",
+  "My sources say no.",
+  "Outlook not so good.",
+  "Very doubtful.",
+];
+
 function shakeBall() {
-  //Write your code in here
+  console.log("The ball has shaken!");
+
+  let randonIndex = Math.floor(Math.random() * answers.length);
+  let result = answers[randonIndex];
+  return result;
 }
 
+// console.log(shakeBall());
+
 /* 
   This function should say whether the answer it is given is
     - very positive
@@ -58,8 +91,37 @@ function shakeBall() {
 
   This function should expect to be called with any value which was returned by the shakeBall function.
 */
+let answer = shakeBall();
+// console.log(answer);
+
 function checkAnswer(answer) {
-  //Write your code in here
+  if (
+    answer === "It is certain." ||
+    answer === "It is decidedly so." ||
+    answer === "Without a doubt." ||
+    answer === "Yes - definitely." ||
+    answer === "You may rely on it."
+  ) {
+    return "very positive";
+  } else if (
+    answer === "As I see it, yes." ||
+    answer === "Most likely." ||
+    answer === "Outlook good." ||
+    answer === "Yes." ||
+    answer === "Signs point to yes."
+  ) {
+    return "positive";
+  } else if (
+    answer === "Reply hazy, try again." ||
+    answer === "Ask again later." ||
+    answer === "Better not tell you now." ||
+    answer === "Cannot predict now." ||
+    answer === "Concentrate and ask again."
+  ) {
+    return "negative";
+  } else {
+    return "very negative";
+  }
 }
 
 /* 
@@ -101,7 +163,9 @@ test("magic 8 ball returns different values each time", () => {
     );
   }
 
-  let seenPositivities = new Set(Array.from(seenAnswers.values()).map(checkAnswer));
+  let seenPositivities = new Set(
+    Array.from(seenAnswers.values()).map(checkAnswer)
+  );
   if (seenPositivities.size < 2) {
     throw Error(
       "Expected to random answers with different positivities each time shakeBall was called, but always got the same one"

mandatory/1-syntax-errors.js

@@ -1,16 +1,16 @@
 // There are syntax errors in this code - can you fix it to pass the tests?
 
-function addNumbers(a b c) {
+function addNumbers(a, b, c) {
   return a + b + c;
 }
 
-function introduceMe(name, age)
-  return `Hello, my {name}` is "and I am $age years old`;
-
+function introduceMe(name, age) {
+  return `Hello, my name is ${name} and I am ${age} years old`;
+}
 function getTotal(a, b) {
-  total = a ++ b;
+  total = a + b;
 
-  return "The total is total";
+  return `The total is ${total}`;
 }
 
 /* 

mandatory/2-logic-error.js

@@ -1,16 +1,15 @@
 // The syntax for these functions is valid but there are some errors, find them and fix them
 
 function trimWord(word) {
-  return wordtrim();
+  return word.trim();
 }
 
 function getStringLength(word) {
-  return "word".length();
+  return word.length;
 }
 
 function multiply(a, b, c) {
-  a * b * c;
-  return;
+  return a * b * c;
 }
 
 /* 

mandatory/3-function-output.js

@@ -2,13 +2,17 @@
 function getRandomNumber() {
   return Math.random() * 10;
 }
+// that function using Math method and random . so working together it return random number between 0 and 10
 
 // Add comments to explain what this function does. You're meant to use Google!
 function combine2Words(word1, word2) {
   return word1.concat(word2);
 }
+// Method concat joins two patanteses together to single string
 
 function concatenate(firstWord, secondWord, thirdWord) {
+  return firstWord.concat(" ", secondWord, " ", thirdWord);
+
   // Write the body of this function to concatenate three words together.
   // Look at the test case below to understand what this function is expected to return.
 }

mandatory/4-tax.js

@@ -5,7 +5,9 @@
   Sales tax is 20% of the price of the product.
 */
 
-function calculateSalesTax() {}
+function calculateSalesTax(num) {
+  return num + num * 0.2;
+}
 
 /*
   CURRENCY FORMATTING
@@ -17,8 +19,13 @@ function calculateSalesTax() {}
   Remember that the prices must include the sales tax (hint: you already wrote a function for this!)
 */
 
-function addTaxAndFormatCurrency() {}
+function addTaxAndFormatCurrency(sele) {
+  let selesWithTaxes = calculateSalesTax(sele);
+  let plusDecimalToSeles = selesWithTaxes.toFixed(2);
 
+  return "£" + plusDecimalToSeles;
+  // return "£" + calculateSalesTax(sele).toFixed(2)
+}
 /* 
 ===================================================
 ======= TESTS - DO NOT MODIFY BELOW THIS LINE =====