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//Mock interview
//reverse sentence
const reverseSentence = str => {
if (typeof str !== "string" || !str.length) {
return null;
}
const smallStr = str
.toLowerCase()
.split("")
.reverse()
.join("");
return smallStr;
};
//tests
console.log(reverseSentence("") === null);
console.log(reverseSentence(123) === null);
console.log(reverseSentence([1, 2, 3, 4]) === null);
console.log(reverseSentence("smart work") === "krow trams");
console.log(reverseSentence("good job") === "boj doog");
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
const operationAnagram = (str1, str2) => {
if (
typeof str1 !== "string" ||
typeof str2 !== "string" ||
!str1.length ||
!str2.length
) {
return null;
}
const input1 = str1.split("");
const count1 = {};
const input2 = str2.split("");
const count2 = {};
input1.forEach(item => {
if (count1[item]) {
count1[item] = count1[item] + 1;
} else {
count1[item] = 1;
}
});
input2.forEach(item => {
if (count2[item]) {
count2[item] = count2[item] + 1;
} else {
count2[item] = 1;
}
});
const key1 = Object.keys(count1);
for (let key of key1) {
if (count1[key] !== count2[key]) {
return false;
}
}
return true;
};
//tests
console.log(operationAnagram("cheerios", "") === null, "test 1");
console.log(operationAnagram("", "cake") === null, "test 2");
console.log(operationAnagram("kite", "apple") === false, "test 3");
console.log(operationAnagram("mary", "army") === true, "test 4");
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//Anagram challenge
const isAnagram = (str1, str2) => {
if (
typeof str1 !== "string" ||
typeof str2 !== "string" ||
!str1.length ||
!str2.length
) {
return null;
}
const result1 = str1
.toLowerCase()
.split("")
.sort()
.join("");
const result2 = str2
.toLowerCase()
.split("")
.sort()
.join("");
if (result1.length !== result2.length) {
return false;
}
if (result1 !== result2) {
return false;
}
return true;
};
//tests
console.log(isAnagram("cheerios", "") === null, "test 1");
console.log(isAnagram("", "cake") === null, "test 2");
console.log(isAnagram("kite", "apple") === false, "test 3");
console.log(isAnagram("mary", "army") === true, "test 4");
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////
//find the largest array from an array of arrays
const twoDimArr = arr => {
let largest = [];
let num;
for (let i = 0; i < arr.length; i++) {
for (let j = 0; j < arr[i].length; j++) {
num = Math.max(...arr[i]);
}
largest.push(num);
}
return largest;
};
//tests
console.log(
twoDimArr([
[1, 2, 3],
[4, 5, 6],
[7, 8, 9],
[10, 11, 12],
[13, 14, 15]
])
);
//Confirm ending
const confirmEnding = (str, target) => {
if (
typeof str !== "string" ||
typeof target !== "string" ||
!str.length ||
!target.length
) {
return false;
}
const words = str.split("");
if (target === words[words.length - 1]) {
return true;
} else {
return false;
}
};
//tests
console.log(confirmEnding("pancakes", "") === false, "test 1");
console.log(confirmEnding("", "m") === false, "test 2");
console.log(confirmEnding("", "") === false, "test 3");
console.log(confirmEnding("maple", "e") === true, "test 4 ");
console.log(confirmEnding("tuna", "a") === true, "test 5");
//Another method
const confirmEnd = (str, target) => {
if (str.endsWith(target)) {
return true;
} else {
return false;
}
};
//tests
console.log(confirmEnd("maple", "e") === true, "test extra 1 ");
console.log(confirmEnd("tunafish", "h") === true, "test extra 2");
console.log(confirmEnd("misosoup", "h") === false, "test extra 2");
//Repeat string num times
const repeatNumTimes = (str, num) => {
if (
typeof str !== "string" ||
!str.length ||
!Number.isFinite(num) ||
num < 0
) {
return false;
}
let final = "";
for (let i = 0; i < num; i++) {
final = final + str;
}
return final;
};
//tests
console.log(repeatNumTimes("", 3) === false, "test 1");
console.log(repeatNumTimes("abc", -1) === false, "test 2");
console.log(repeatNumTimes("xyz", 2) === "xyzxyz", "test 3");
console.log(repeatNumTimes("we won", 2) === "we wonwe won", "test 4");
//alternate method
const repeatNtimes = (str, num) => {
return str.repeat(num);
};
//tests
console.log(repeatNtimes("xyz", 3) === "xyzxyzxyz", "test extra 1");
//Truncate string
//Truncate a string (first argument) if it is longer than the given
//maximum string length (second argument). Return the truncated string with
//a ... ending, else return string.
const truncateString = (str, num) => {
if (
typeof str !== "string" ||
!str.length ||
!Number.isFinite(num) ||
num < 0
) {
return false;
}
if (str.length <= num) {
return str;
} else {
return str.slice(0, num - 3) + "...";
}
};
//tests
console.log(truncateString("", 6) === false);
console.log(truncateString("shilpi", -3) === false);
console.log(truncateString("shilpi", 6) === "shilpi");
console.log(truncateString("hey whats up", 5) === "he...");
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//18-09-2020, Thursday
//Find out whether given series is a AP or not
const mathSequenceAP = arr => {
if (!Array.isArray(arr) || !arr.length) {
return null;
}
for (let i = 1; i < arr.length - 1; i++) {
if (arr[i] - arr[i - 1] !== arr[i + 1] - arr[i]) {
return false;
}
}
return true;
};
//tests
console.log(mathSequenceAP(1, 2, 3, 4, 5, 6) === null, "test 1");
console.log(mathSequenceAP("It's a trap") === null, "test 2");
console.log(mathSequenceAP([]) === null, "test 3");
console.log(mathSequenceAP([2, 4, 6, 8]) === true, "test 4");
console.log(mathSequenceAP([2, 4, 6, 9]) === false, "test 5");
console.log(mathSequenceAP([2, 3, 6, 8]) === false, "test 6");
//Reverse a string
const reverseString = str => {
if (typeof str !== "string" || !str.length) {
return null;
}
const results = [];
const strSplit = str.split("");
for (let i = strSplit.length - 1; i >= 0; i--) {
results.push(strSplit[i]);
}
return results.join("");
};
//tests
console.log(reverseString("") === null, "test 1");
console.log(reverseString(123) === null, "test 2");
console.log(reverseString("hello") === "olleh", "test 3");
console.log(reverseString("shilpi") === "iplihs", "test 4");
console.log(reverseString("sweet") === "teews", "test 5");
//tutorial's method
const stringReverse = str => {
return str
.split("")
.reverse()
.join("");
};
//Another way
const strReverse = str => {
let results = "";
for (let i = str.length - 1; i >= 0; i--) {
results = results + str[i];
}
return results;
};
//Factorial
const factorial = num => {
if (!Number.isInteger(num)) {
return null;
}
let results = 1;
for (let i = num; i >= 1; i--) {
results = results * i;
}
return results;
};
//tests
console.log(factorial("string") === null, "test 1");
console.log(factorial([1, 2, 3, 4]) === null, "test 2");
console.log(factorial(3) === 6, "test 3");
console.log(factorial(6) === 720, "test 4");
//Palindrome
const palindrome = str => {
if (typeof str !== "string" || !str.length) {
return null;
}
const smallStr = str.toLowerCase().replace(/[\W_]/, "");
const reverseStr = smallStr
.split("")
.reverse()
.join("");
if (smallStr === reverseStr) {
return true;
} else {
return false;
}
};
//tests
console.log(palindrome(123) === null, "test 1");
console.log(palindrome("") === null, "test 2");
console.log(palindrome("eye") === true, "test 3");
console.log(palindrome("shilpi") === false, "test 4");
console.log(palindrome("level") === true, "test 5");
console.log(palindrome("race car") === true, "test 6");
//Longest word length
const LongestWordLength = str => {
if (typeof str !== "string" || !str.length) {
return null;
}
const longestWord = str.split(" ");
let longest = "";
for (let i = 0; i < longestWord.length; i++) {
if (longestWord[i].length > longest.length) {
longest = longestWord[i];
}
}
return longest.length;
};
//tests
console.log(LongestWordLength("") === null, "test 1");
console.log(LongestWordLength(123) === null, "test 2");
console.log(LongestWordLength("my name is shilpi") === 6, "test 3");
console.log(LongestWordLength("cats are awesome") === 7, "test 4");
console.log(LongestWordLength("wishing well") === 7, "test 5");
//tutorial
const longestWord = str => {
return str.split(" ").sort(function(a, b) {
return b.length - a.length;
})[0].length;
};
//19-09-2020, Friday
//Title case a sentence
const titleCase = str => {
if (typeof str !== "string" || !str.length) {
return null;
}
const smallStr = str.toLowerCase().split(" ");
for (let i = 0; i < smallStr.length; i++) {
smallStr[i] = smallStr[i][0].toUpperCase() + smallStr[i].slice(1);
}
return smallStr.join(" ");
};
//test cases
console.log(titleCase("Shilpi christy"));
console.log(titleCase(123) === null, "test 1");
console.log(titleCase("") === null, "test 2");
console.log(titleCase("my name is Shilpi") === "My Name Is Shilpi", "test 3");
console.log(titleCase("flying kites") === "Flying Kites", "test 4");
console.log(titleCase("Organic farming") === "Organic Farming", "test 5");
//Another way
const caseTitle = str => {
return str
.toLowerCase()
.split(" ")
.map(item => {
return item[0].toUpperCase() + item.slice(1);
})
.join(" ");
};
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
//Older Challenges
//Programming practice
//write a js program to check two numbers and return true is one of them is
//100 or their sum is 100
const isHundred = (num1, num2) => {
if (typeof num1 !== "number" || typeof num2 !== "number" || !num1 || !num2) {
return null;
}
if (num1 === 100 || num2 === 100 || num1 + num2 === 100) {
return true;
} else {
return false;
}
};
//0(1)
//tests
console.log(isHundred(100, 1) === true);
console.log(isHundred(1, 100) === true);
console.log(isHundred(10, 19) === false);
console.log(isHundred(15, 75) === false);
console.log(isHundred(50, 50) === true);
console.log(isHundred(1, "shilpi") === null);
console.log(isHundred(1) === null);
//Write a program to get the extension of a filename
const getFileExtension = str => {
if (
typeof str !== "string" ||
str.lastIndexOf(".") === str.length - 1 ||
str.lastIndexOf(".") === -1
) {
return null;
}
const result = str.slice(str.lastIndexOf("."));
return result;
};
//tests
console.log(getFileExtension("index.html") === ".html");
console.log(getFileExtension("index.css") === ".css");
console.log(getFileExtension("index.js") === ".js");
console.log(getFileExtension("index") === null);
console.log(getFileExtension("index.") === null);
console.log(getFileExtension(123) === null);
// write a program in js that replace every character in a given string with
// the character following it in a alphabet
const moveCharacterForword = str => {
if (typeof str !== "string" || !str.length) {
return null;
} else {
return str
.split("")
.map(char => String.fromCharCode(char.charCodeAt(0) + 1))
.join("");
}
};
//tests
console.log(moveCharacterForword("abc") === "bcd", "test 1");
console.log(moveCharacterForword("") === null, "test 2");
console.log(moveCharacterForword(123) === null, "test 3");
//write a js program to return a current date
const formatDate = (date = new Date()) => {
const day = date.getDate();
const month = date.getMonth();
const year = date.getFullYear();
return `${day}/${month}/${year}`;
};
console.log(formatDate());
const now = new Date();
console.log(now);
//Write a js program to create a new string adding "New!" in front of
//a new given string , if the given string already has "New!" return the
//original string
const addingNew = str => {
if (typeof str !== "string" || !str.length) {
return null;
}
const newStr = str.split(" ");
if (newStr[0] === "New!") {
return str;
} else {
return newStr.splice(0, 0, "New!").join(" ");
}
};
//tests
console.log(addingNew("name is shilpi") === "New! name is shilpi");
console.log(addingNew(123) === null);
console.log(addingNew("") === null);
console.log(addingNew("New! offers") === "New! offers");
//alternate method
const addNew = string =>
string.indexOf("New!" === 0) ? string : `New! ${string}`;
//tests
console.log(addNew("Discounts"));
console.log(addNew("New! offers"));
@ShilpiMaurya
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Author

ShilpiMaurya commented Sep 3, 2020

Hey bhaiya....i need some help in this program. Its not working.

const addingNew = str => {
  if (typeof str !== "string" || !str.length) {
    return null;
  }
  const newStr = str.split(" ");
  if (newStr[0] === "New!") {
    return str;
  } else {
    return newStr.splice(0, 0, "New!").join(" ");
  }
};

//tests

console.log(addingNew("name is shilpi") === "New! name is shilpi");

@ShilpiMaurya
Copy link
Author

ShilpiMaurya commented Sep 3, 2020

and i need help in this as well. its also not working.
const addNew = string =>
string.indexOf("New!" === 0) ? string : New! ${string};

//tests

console.log(addNew("Discounts"));

@vbUNext
Copy link

vbUNext commented Sep 3, 2020

Hey bhaiya....i need some help in this program. Its not working.
const addingNew = str => {
if (typeof str !== "string" || !str.length) {
return null;
}
const newStr = str.split(" ");
if (newStr[0] === "New!") {
return str;
} else {
return newStr.splice(0, 0, "New!").join(" ");
}
};

//tests

console.log(addingNew("name is shilpi") === "New! name is shilpi");

Suggestions:

  1. Please write code with syntax highlighting like js your code . Otherwise, code is really difficult to read.
  2. Line#111: string.indexOf("New!") === 0, not string.indexOf("New!" === 0)
  3. Line#7: Suggestion Number.isFinite() or Number.isInteger()
  4. For running tests, can use code block like this:
const testCases = [
  { input: 6, output: 8 },
  { input: 1, output: 1 },
  { input: 9, output: 34 },
];

testCases.forEach(({ input, output }, index) => {
  console.log(`test ${index}: ${fib(input) === output ? "Succeed" : "Failed"}`);
});

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