Spinal Tap Case - 《freecodecamp》

Spinal Tap Case

Convert a string to spinal case. Spinal case is all-lowercase-words-joined-by-dashes.

spinalCase("This Is Spinal Tap") should return the string this-is-spinal-tap.

spinalCase("thisIsSpinalTap") should return the string this-is-spinal-tap.

spinalCase("The_Andy_Griffith_Show") should return the string the-andy-griffith-show.

spinalCase("Teletubbies say Eh-oh") should return the string teletubbies-say-eh-oh.

spinalCase("AllThe-small Things") should return the string all-the-small-things.

如何识别大写字母???

Split the string at one of the following conditions (converted to an array)
- a whitespace character [\s] is encountered
- underscore character [_] is encountered
- or is followed by an uppercase letter [(?=[A-Z])]
Join the array using a hyphen (-)
Lowercase the whole resulting string

Use ?= to match a string that’s followed by a specific substring:

/Roger(?=Waters)/

/Roger(?= Waters)/.test(‘Roger is my dog’) //false

/Roger(?= Waters)/.test(‘Roger is my dog and Roger Waters is a famous musician’)

//true

?! performs the inverse operation, matching if a string is not followed by a specific substring:

/Roger(?!Waters)/

/Roger(?! Waters)/.test(‘Roger is my dog’) //true

/Roger(?! Waters)/.test(‘Roger is my dog and Roger Waters is a famous musician’)

//false

function spinalCase(str) {
  str = str.split(/\s|_|(?=[A-Z])/).join("-").toLowerCase();
  return str;
}
console.log(
spinalCase('thisIsSpinalTap')
)