Problem solving with JavaScript

Create JavaScript function that meets some requirements.

Table off content

1. Fail / Pass Averages
2. Swap Characters
3. Move Capital Letters
4. Check Date
5. How many Days Between
6. Leading zeros

1. Fail / Pass Averages

• Receives an array of numbers as a parameter, with each integer being a mark out of 100.
• The function should return an array consisting of all the averages less than 50, followed by the average of all the mark more than 50.
• both averages should be rounded to the nearest whole number.
• If there are no failing marks (< 50), then the average fail mark should be set to -1.
• If there are no passing marks (< 50), then the average pass mark should be set to -1.

  Test Case:
  functionName([63, 65, 33])) --> [33,64] 
  functionName([63, 62, 100, 100])) --> [-1, 81]
  functionName([33, 42, 20, 10])) --> [26, -1]

Answer

function failPassAverage(arr) {
  const failArr = arr.filter((i) => i < 50);
  const passArr = arr.filter((i) => i >= 50 && i != 0);

  const failAvg =
    failArr.length !== 0
      ? Math.round(failArr.reduce((a, b) => a + b) / failArr.length)
      : -1;
  const passAvg =
    passArr.length !== 0
      ? Math.round(passArr.reduce((a, b) => a + b) / passArr.length)
      : -1;

  return [failAvg, passAvg];
}

2. Swap Characters

• function take three arguments, a string, character 1 and character 2
• The function replaces all instances of c1 with c2, and vice versa
• The function returns the updated string

  Test Case:
  functionName("aabbccc", "a", "b) --> "bbaaccc" 
  functionName("random w#rds writt&n h&r&", "#", "&") --> "random w&rds writt#n h#r#"
  functionName("128 895 556 788 999", "8", "9") -->  "129 985 556 799 888"

Answer

function swapCharactersInString(str, c1, c2) {
  let stringArr = str.split("");

  for (let i = 0; i < stringArr.length; i++) {
    if (stringArr[i] === c1) {
      stringArr[i] = c2;
    } else if (stringArr[i] === c2) {
      stringArr[i] = c1;
    }
  }
  return stringArr.join("");
}

3. Move Capital Letters

• That takes in a string parameter, of mixed casing (mix of upper and lowercase letters)
• The function moves all capital letters to the front of a word.
• The uppercase letters moved to the front, maintain their original relative order
• The lowercase letters moved to the back front, maintain their original relative order

  Test Case:
  functionName("hApPy") --> "APhpy"
  functionName("moveMENT") --> "MENTmove"
  functionName("shOrtCAKE") -->  "OCAKEshrt"

Answer

function moveCapitalLetter(str) {
  let cap = "";
  let small = "";
  for (let i = 0; i < str.length; i++) {
    if (str[i] >= "A" && str[i] <= "Z") {
      cap += str[i];
    } else {
      small += str[i];
    }
  }
  return cap + small;
}

Answer 2

function moveCapitalLetter(str) {
  const res = [...str].sort((a, b) => (isCaps(a) ? (isCaps(b) ? 0 : -1) : 0));
  return res.join("");

  function isCaps(c) {
    return c.charCodeAt() >= 65 && c.charCodeAt() <= 90;
  }
}

4. Check Date

• Receives a string as a parameter.
• The function returns a Boolean indicating if the parameter string passed, is a valid date. True indicates a valid date was provided o False indicates that a valid date was not provided.
• A valid date string, will have only the full month name (ex “January” not “Jan”) and a day number.A year will not be provided and thus your logic need not be concerned in that regard
• The string parameter can contain any number of spaces, but the month name must always start at the first non-space character from the beginning of the string
• The day number part of the date string to be tested could contain alphabetic characters and thus making it invalid
• You may assume February only has 28 days in it.

  Test Case:
  functionName("aabbccc", "a", "b) --> "bbaaccc" 
  functionName("random w#rds writt&n h&r&", "#", "&") --> "random w&rds writt#n h#r#"
  functionName("128 895 556 788 999", "8", "9") -->  "129 985 556 799 888"
  functionName("January 21"))  -->  true
  functionName("Auust 3")) -->  false
  functionName(" June 15B ")) -->  false
  functionName("February 0")) --> false
  functionName(" December 3K1"))  -->  false
  functionName("February 29"))  -->  false
  functionName(" February 28 "))  -->  true

Answer

function checkValidDate(dateStr) {
  const MONTH = {
    January: "January",
    February: "February",
    March: "March",
    April: "April",
    May: "May",
    June: "June",
    July: "July",
    August: "August",
    September: "September",
    October: "October",
    November: "November",
    December: "December",
  };
  let [month, day] = filterUndefined(splitToArr(dateStr, " "));

  if (month === MONTH.January && day <= 31 && day != 0) return true;
  else if (month === MONTH.February && day <= 28 && day != 0) return true;
  else if (month === MONTH.March && day <= 31 && day != 0) return true;
  else if (month === MONTH.April && day <= 30 && day != 0) return true;
  else if (month === MONTH.May && day <= 31 && day != 0) return true;
  else if (month === MONTH.June && day <= 30 && day != 0) return true;
  else if (month === MONTH.July && day <= 31 && day != 0) return true;
  else if (month === MONTH.August && day <= 30 && day != 0) return true;
  else if (month === MONTH.September && day <= 31 && day != 0) return true;
  else if (month === MONTH.October && day <= 30 && day != 0) return true;
  else if (month === MONTH.November && day <= 31 && day != 0) return true;
  else if (month === MONTH.December && day <= 30 && day != 0) return true;
  else return false;

  function filterUndefined(arr) {
    let newArr = [];
    for (let i = 0; i < arr.length; i++) {
      if (arr[i] !== undefined) {
        newArr = [...newArr, arr[i]];
      }
    }
    return newArr;
  }

  function splitToArr(string, separator) {
    let cache = [];
    let cachInt = 0;
    let lastWord = "";
    for (let i = 0; i < string.length; i++) {
      if (string[i] == separator) {
        cachInt++;
        lastWord = "";
      } else {
        if (lastWord !== " ") {
          lastWord += string[i];
          cache[cachInt] = lastWord;
        }
      }
    }
    return cache;
  }
}

5. How many Days Between

• Create a function that takes two valid dates as arguments
• The function returns the number of days between str_date1 and str_date2

  Test Case:
  
  functionName("June 14, 2021", "June 20, 2021")  --> 6
  functionName("December 29, 2021", "January 1, 2022")  --> 3
  functionName("July 20, 2021", "July 30, 2021")  --> 10

Answer

function getDaysBetweenTwoDate(str1, str2) { const date1 = new Date(str1); const date2 = new Date(str2); const startDay = Math.floor(date1.getTime() / (60 * 60 * 24 * 1000)); const endDay = Math.floor(date2.getTime() / (60 * 60 * 24 * 1000)); return endDay - startDay; }

6. Leading Zeros

• That takes in a string number as an argument
• The function returns the number removing any trailing and/or leading zeros.
• Trailing zeros are the zeros after a decimal point which don’t affect the value of the number
• Leading zeros are the zeros before a number which don’t affect the value of the number

  Test Case:
  
  functionName("230.000")  --> 230
  functionName("00402")  --> 402
  functionName("03.1400")  --> 3.14
  functionName("30")  --> 30

Answer

function removeLeadingZeros(num) {
  return +num;
}

7. Capitalize first Letter of Each Word

• That takes in a string as an argument.
• The function converts first character of each word to uppercase.
• The function returns the newly formatted string.

  Test Case:
  
  functionName("This is a title")  --> "This Is A Title"
  functionName("capitalize every word")  --> "Capitalize Every Word"                                  
  functionName("I Like Pizza")  --> "I Like Pizza"
  functionName("PIZZA PIZZA PIZZA")  --> "PIZZA PIZZA PIZZA"

Answer

function capFirstLetterOfEachWord(str) {
  let result = "";
  let arr = splitToArr(str, " ");
  let newStr = "";
  for (let i = 0; i < arr.length; i++) {
    let word = "";
    for (let j = 0; j < arr[i].length; j++) {
      let chh = "";
      if (j == 0) {
        if (arr[i][j] >= "a" && arr[i][j] <= "z") {
          chh = String.fromCharCode(arr[i].charCodeAt(0) - 32);
        } else {
          chh += arr[i][j];
        }
      } else {
        chh += arr[i][j];
      }
      word += chh;
    }
    newStr += word + " ";
  }
  for (let i = 0; i < newStr.length - 1; i++) {
    result += newStr[i];
  }
  return result;

  function splitToArr(string, separator) {
    let cache = [];
    let cachInt = 0;
    let lastWord = "";
    for (let i = 0; i < string.length; i++) {
      if (string[i] == separator) {
        cachInt++;
        lastWord = "";
      } else {
        if (lastWord !== " ") {
          lastWord += string[i];
          cache[cachInt] = lastWord;
        }
      }
    }
    return cache;
  }
}