Split a string with regular expression lookarounds using javascript

I want to use String.prototype.split to split the string if the previous character is not equal to the next character, here's the target result:

'abcd' => ['a', 'b', 'c', 'd']

'aaabbbccd' => ['aaa', 'bbb', 'cc', 'd']

I know it's possible to split a string by only lookbacks:

const result = 'aaabbbccd'.split(/(?<=a)/);
console.log(result);  // ["a", "a", "a", "bbbccd"]

So I wanted to find an expression to find the delimiter of two characters that its lookback is not equal to lookahead.

But I tried this, and it doesn't work:

const result = 'aaabbcccd'.split(/(?<!\2)(?=.)/);
console.log(result);  // ['a', 'a', 'a', 'b', 'b', 'c', 'c', 'c', 'd']

So is there a regular expression to achieve this? Or it's just simply impossible to do that with regex?

Solution

Using backreferences, you can use .match() instead of .split() to get your desired result like so:

const r1 = 'abcd'.match(/(.)\1*/g);
const r2 = 'aaabbcccd'.match(/(.)\1*/g);
console.log(r1); // ['a', 'b', 'c', 'd']
console.log(r2); // ['aaa', 'bb', 'ccc', 'd']

This will match any character (.), followed by the same character \1 zero or more times