Javascript Scripts

Here is the list of various scripts written using javascript. They are made through the exploration of the language so you are free to use them as you wish.

The list of scripts

1. Roman numeral converter
2. Palindrome checker
3. Factorial
4. Telephone checker
5. Decimals fix
6. Title case
7. Fix runts

Details

Roman numeral converter

Converts the Arabic numbers to roman and vice versa. For converting from Arabic to roman use function convertToRoman(num) with the number as a parameter and for converting from roman to Arabic use function convertToArabic(str) with the string as a parameter that is passed to the function. Both functions return a number or a letter, depending on which function you use.

console.log(convertToRoman(3999));
// Output: MMMCMXCIX
console.log(convertToArabic("MMMCMXCIX"));
// Output: 3999

Palindrome checker

Checks if a word or a sentence is a palindrome. A palindrome is a word or a sentence that's spelled the same way both forward and backward, ignoring the punctuation, case, and spacing. The function works by removing all non-alphanumeric characters (punctuation, spaces, and symbols) and turns everything into the same case (lower or upper case) to check for palindromes. The result of the function is a boolean (true or false) and it depends if the palindrome is found or not.

console.log(palindrome("1 eye for of 1 eye."));
// Output: true

Factorial

Factorial is a function that calculates the factorial from a given number that is passed as a parameter.

console.log(factorial(10));
// Output: 3628800

Telephone checker

Checks if a telephone number is in valid format. The parameter that is passed to the function is a string and the function returns a boolean as a result.

console.log(telephoneCheck("1 555)555-5555"));
// Output: false
console.log(telephoneCheck("1 555-555-5555"));
// Output: true

Decimals fix

Decimals fix overcomes Javascript floating-point rounding errors issues when trying to add or subtract two numbers with decimal spaces. For example, 0.1 + 0.2 === 0.30000000000000004. This happens because all javascript numbers are double-precision floating-point, so to fix this we have to determine how many decimals spaces there are, multiply to convert numbers to integers, perform addition or subtraction, and then divide again to get the decimal point.

let a = 0.1;
let b = 0.2;
let maxDecimals = getMaxDecimalDivider(1, Math.max(countDecimalSpaces(a), countDecimalSpaces(b)));

console.log(a + b);
// Output: 0.30000000000000004
console.log((convertDecimalsToInteger(a, 1, maxDecimals) + convertDecimalsToInteger(b, 1, maxDecimals)) / maxDecimals);
// Output: 0.3

Title case

The function that converts the string that is passed as a parameter to the title case.

let str = 'title  case here';

console.log(titleCase(str));
// Output: Title Case Here

Fix runts

Function that fixes runts from the string (paragraph). It replaces the last whitespace character with the   (non-breaking space character)

let str = "640K ought to be enough for anybody. (Bill Gates, 1981) The best thing about a boolean is even if you are wrong, you are only off by a bit. (Anonymous) I think Microsoft named .Net so it wouldn’t show up in a Unix directory listing. (Oktal) Come to think of it, there are already a million monkeys on a million typewriters, and Usenet is nothing like Shakespeare. (Blair Houghton)"

console.log(fixRunts(str))
// Output: 640K ought to be enough for anybody. (Bill Gates, 1981) The best thing about a boolean is even if you are wrong, you are only off by a bit. (Anonymous) I think Microsoft named .Net so it wouldn’t show up in a Unix directory listing. (Oktal) Come to think of it, there are already a million monkeys on a million typewriters, and Usenet is nothing like Shakespeare. (Blair Houghton)