How to remove whitespace chunks ending with a newline from string?

You could use a single pattern, and in the replacement use a comma and a single space.

[^\S\r\n]*[\r\n]+ 

• [^\S\r\n]* Negated character class, match 0+ times a whitespace char except newlines
• [\r\n]+ Match 1+ newlines (for a single newline, use \r?\n)

Regex demo

 const regex = /[^\S\r\n]*[\r\n]+/g; const str = `Stehn Stehn Simchart Simchart Stehn Stehn Stehn Stehn Stehn `; const result = str.replace(regex, `, `); console.log(result);

If your string is:

let s = "a b c d e \nf g h\n\ni"; 

Then you can strip with:

s.split(/\s+/) 

And combine:

s.split(/\s+/).join(','); 

If instead it's a newline thing and you want to trim, then why not just split? Easier than replacing, splitting, trimming, and rejoining:

s.split(/\r?\n|\r/).map(s => s.trim()).join(', ') 

Since you want to substitute whitespace with , you must write a regex that matches whitespaces

Regex: /\b\s+\b/gm

g: global mode

m: multiline mode

Now at this point your regex should match all the spaces. Now all you have to do is replace them with ,

Note that I am using word boundaries here since you do not want , at the end of your last string.

Try this.

function removeAllBlankSpaces(str) { return str.split('').filter(s => s != ' ').join(''); } console.log(removeAllBlankSpaces('str ing');