Slugify & Deslugify

function 
function capitalizeFirstLetter(str: string): string
capitalizeFirstLetter(
str: string
str: string) {
  if (
str: string
str.
String.length: number
Returns the length of a String object.
length == 0) return "";
  if (
str: string
str.
String.length: number
Returns the length of a String object.
length == 1) return 
str: string
str[0].
String.toUpperCase(): string
Converts all the alphabetic characters in a string to uppercase.
toUpperCase();
  return 
str: string
str[0].
String.toUpperCase(): string
Converts all the alphabetic characters in a string to uppercase.
toUpperCase() + 
str: string
str.
String.substring(start: number, end?: number): string
Returns the substring at the specified location within a String object.
@param ― start The zero-based index number indicating the beginning of the substring.
@param ― end Zero-based index number indicating the end of the substring. The substring includes the characters up to, but not including, the character indicated by end.
If end is omitted, the characters from start through the end of the original string are returned.
substring(1);
}
function 
function deSlugifyStr(str: string): string
deSlugifyStr(
str: string
str: string) {
  // if string doesn't contain a '-' or '_' just return back the capitalized word
  if (!
str: string
str.
String.includes(searchString: string, position?: number): boolean
Returns true if searchString appears as a substring of the result of converting this
object to a String, at one or more positions that are
greater than or equal to position; otherwise, returns false.
@param ― searchString search string
@param ― position If position is undefined, 0 is assumed, so as to search all of the String.
includes("-") && !
str: string
str.
String.includes(searchString: string, position?: number): boolean
Returns true if searchString appears as a substring of the result of converting this
object to a String, at one or more positions that are
greater than or equal to position; otherwise, returns false.
@param ― searchString search string
@param ― position If position is undefined, 0 is assumed, so as to search all of the String.
includes("_")) return 
function capitalizeFirstLetter(str: string): string
capitalizeFirstLetter(
str: string
str);
  // replaces '-' or '_ with ' '
  const 
const StrWithDashesAndHypensReplacedWithSpaces: string
StrWithDashesAndHypensReplacedWithSpaces = 
str: string
str.
String.replace(searchValue: {
    [Symbol.replace](string: string, replaceValue: string): string;
}, replaceValue: string): string (+3 overloads)
Passes a string and
{@linkcode
replaceValue
}
to the [Symbol.replace] method on
{@linkcode
searchValue
}
. This method is expected to implement its own replacement algorithm.
@param ― searchValue An object that supports searching for and replacing matches within a string.
@param ― replaceValue The replacement text.
replace(/-/g, "  ").
String.replace(searchValue: {
    [Symbol.replace](string: string, replaceValue: string): string;
}, replaceValue: string): string (+3 overloads)
Passes a string and
{@linkcode
replaceValue
}
to the [Symbol.replace] method on
{@linkcode
searchValue
}
. This method is expected to implement its own replacement algorithm.
@param ― searchValue An object that supports searching for and replacing matches within a string.
@param ― replaceValue The replacement text.
replace(/_/g, "  ");
  let 
let deSlugifiedStr: string
deSlugifiedStr = "";
  
const StrWithDashesAndHypensReplacedWithSpaces: string
StrWithDashesAndHypensReplacedWithSpaces.
String.split(separator: string | RegExp, limit?: number): string[] (+1 overload)
Split a string into substrings using the specified separator and return them as an array.
@param ― separator A string that identifies character or characters to use in separating the string. If omitted, a single-element array containing the entire string is returned.
@param ― limit A value used to limit the number of elements returned in the array.
split(" ").
Array<string>.forEach(callbackfn: (value: string, index: number, array: string[]) => void, thisArg?: any): void
Performs the specified action for each element in an array.
@param ― callbackfn A function that accepts up to three arguments. forEach calls the callbackfn function one time for each element in the array.
@param ― thisArg An object to which the this keyword can refer in the callbackfn function. If thisArg is omitted, undefined is used as the this value.
forEach((
char: string
char) => {
    
let deSlugifiedStr: string
deSlugifiedStr += !!
char: string
char ? 
function capitalizeFirstLetter(str: string): string
capitalizeFirstLetter(
char: string
char) : " ";
  });
  return 
let deSlugifiedStr: string
deSlugifiedStr;
}
function 
function slugifyString(str: string): string
slugifyString(
str: string
str: string) {
  if (typeof 
str: string
str !== "string")
    throw new 
var TypeError: TypeErrorConstructor
new (message?: string, options?: ErrorOptions) => TypeError (+3 overloads)
TypeError(
      `Invalid value passed to slugifyString!: Expected string but received ${typeof 
str: never
str}`,
    );
  return (
    
str: string
str
      .
String.trim(): string
Removes the leading and trailing white space and line terminator characters from a string.
trim()
      .
String.toLowerCase(): string
Converts all the alphabetic characters in a string to lowercase.
toLowerCase()
      //Remove all characters except alphanumeric characters and spaces
      .
String.replace(searchValue: {
    [Symbol.replace](string: string, replaceValue: string): string;
}, replaceValue: string): string (+3 overloads)
Passes a string and
{@linkcode
replaceValue
}
to the [Symbol.replace] method on
{@linkcode
searchValue
}
. This method is expected to implement its own replacement algorithm.
@param ― searchValue An object that supports searching for and replacing matches within a string.
@param ― replaceValue The replacement text.
replace(/[^\w\s]/gi, "")
      //replace all spaces with -
      .
String.replace(searchValue: {
    [Symbol.replace](string: string, replaceValue: string): string;
}, replaceValue: string): string (+3 overloads)
Passes a string and
{@linkcode
replaceValue
}
to the [Symbol.replace] method on
{@linkcode
searchValue
}
. This method is expected to implement its own replacement algorithm.
@param ― searchValue An object that supports searching for and replacing matches within a string.
@param ― replaceValue The replacement text.
replace(/[^a-z0-9]/gi, "-")
  );
}