Regex: match everything but a given string and do not match single characters from that string

Let’s start with the following input.

Input = 'blue, blueblue, b l u e'

I want to match everything that is not the string ‘blue’. Note that blueblue should not match but single characters should (even if present in match string).
From this If I replace the matches with an empty string it should return:

Result = 'blueblueblue'

I have tried with [^\bblue\b]+
but this matches the last four single characters ‘b’, ‘l’,’u’,’e’

>Solution :

If you regex engine support the \K flag, then we can try:

/blue\K|.*?(?=blue|$)/gm

This pattern says to match:

• blue match "blue"
• \K but then forget that match
• | OR
• .*? match anything else until reaching
• (?=blue|$) the next "blue" or the end of the string

Edit:

On JavaScript, we can try the following replacement:

var input = "blue, blueblue, b l u e";
var output = input.replace(/blue|.*?(?=blue|$)/g, (x) => x != "blue" ? "" : "blue");
console.log(output);