feat: add string algorithm in javascript

Javascript/Strings/CheckCamelCase.js

@@ -0,0 +1,15 @@
+// CheckCamelCase method checks the given string is in camelCase or not.
+
+const checkCamelCase = varName => {
+  // firstly, check that input is a string or not.
+  if (typeof varName !== 'string') {
+    return 'not a string.'
+  }
+
+  const reg = /^[a-z][A-Za-z]*$/
+  return reg.test(varName)
+}
+
+console.log(checkCamelCase('myVar'))
+console.log(checkCamelCase('MyVar'))
+console.log(checkCamelCase('my-var'))

Javascript/Strings/CheckFlatCase.js

@@ -0,0 +1,15 @@
+// checkFlatCase method checks if the given string is in flatcase or not.
+
+const checkFlatCase = varname => {
+  // firstly, check that input is a string or not.
+  if (typeof varname !== 'string') {
+    return 'not a string.'
+  }
+
+  const reg = /^[a-z]*$/
+  return reg.test(varname)
+}
+
+console.log(checkFlatCase('myvar'))
+console.log(checkFlatCase('MyVar'))
+console.log(checkFlatCase('my-var'))

Javascript/Strings/CheckKebabCase.js

@@ -0,0 +1,15 @@
+// CheckKebabCase method checks the given string is in kebab-case or not.
+
+const checkSnakeCase = varName => {
+  // firstly, check that input is a string or not.
+  if (typeof varName !== 'string') {
+    return 'not a string.'
+  }
+
+  const reg = /(.*?)-([a-zA-Z])*/
+  return reg.test(varName)
+}
+
+console.log(checkSnakeCase('myVar'))
+console.log(checkSnakeCase('my_var'))
+console.log(checkSnakeCase('my-var'))

Javascript/Strings/CheckPalindrome.js

@@ -0,0 +1,21 @@
+// Palindrome check is case sensitive; i.e. Aba is not a palindrome
+
+const checkPalindrome = str => {
+  // check that input is a string
+  if (typeof str !== 'string') {
+    return 'Not a string'
+  }
+  if (str.length === 0) {
+    return 'Empty string'
+  }
+  // Reverse only works with array, thus convert the string to array, reverse it and convert back to string
+  // return as palindrome if the reversed string is equal to the input string
+  const reversed = [...str].reverse().join('')
+  return str === reversed ? 'Palindrome' : 'Not a Palindrome'
+}
+
+console.log(checkPalindrome('hello'))
+console.log(checkPalindrome(12))
+console.log(checkPalindrome(null))
+console.log(checkPalindrome(undefined))
+console.log(checkPalindrome('level'))

Javascript/Strings/CheckPascalCase.js

@@ -0,0 +1,15 @@
+// CheckPascalCase method checks the given string is in PascalCase or not.
+
+const checkPascalCase = VarName => {
+  // firstly, check that input is a string or not.
+  if (typeof VarName !== 'string') {
+    return 'not a string.'
+  }
+
+  const reg = /^[A-Z][A-Za-z]*$/
+  return reg.test(VarName)
+}
+
+console.log(checkPascalCase('myVar'))
+console.log(checkPascalCase('MyVar'))
+console.log(checkPascalCase('my-var'))

Javascript/Strings/CheckSnakeCase.js

@@ -0,0 +1,15 @@
+// CheckSnakeCase method checks the given string is in snake_case or not.
+
+const checkSnakeCase = varName => {
+  // firstly, check that input is a string or not.
+  if (typeof varName !== 'string') {
+    return 'not a string.'
+  }
+
+  const reg = /(.*?)_([a-zA-Z])*/
+  return reg.test(varName)
+}
+
+console.log(checkSnakeCase('myVar'))
+console.log(checkSnakeCase('my_var'))
+console.log(checkSnakeCase('my-var'))

Javascript/Strings/ConsonantCount.js

@@ -0,0 +1,23 @@
+// Given a string of words or phrases, count the number of consonants.
+
+const vowelCount = value => {
+  if (typeof value !== 'string') {
+    return 'not a string'
+  }
+  const vowels = ['a', 'e', 'i', 'o', 'u']
+
+  let countConsonants = 0
+
+  for (let i = 0; i < value.length; i++) {
+    const char = value[i].toLowerCase()
+    if (!vowels.includes(char)) {
+      countConsonants++
+    }
+  }
+  return countConsonants
+}
+
+console.log(vowelCount('hello'))
+console.log(vowelCount('rythm'))
+console.log(vowelCount(20))
+console.log(vowelCount(null))

Javascript/Strings/ReverseString.js

@@ -0,0 +1,19 @@
+// Reverse a given string
+
+function reverseString (string) {
+  if (typeof string !== 'string') {
+    return 'not a string.'
+  }
+  let reversedString = ''
+  let index
+
+  for (index = string.length - 1; index >= 0; index--) {
+    reversedString += string[index]
+  }
+
+  return reversedString
+}
+
+console.log(reverseString('hello'))
+console.log(reverseString(100))
+console.log(reverseString('world'))

Javascript/Strings/VowelCount.js

@@ -0,0 +1,23 @@
+// Given a string of words or phrases, count the number of vowels.
+
+const vowelCount = value => {
+  if (typeof value !== 'string') {
+    return 'not a string'
+  }
+  const vowels = ['a', 'e', 'i', 'o', 'u']
+
+  let countVowels = 0
+
+  for (let i = 0; i < value.length; i++) {
+    const char = value[i].toLowerCase()
+    if (vowels.includes(char)) {
+      countVowels++
+    }
+  }
+  return countVowels
+}
+
+console.log(vowelCount('hello'))
+console.log(vowelCount('rythm'))
+console.log(vowelCount(20))
+console.log(vowelCount(null))