JavaScript regex whitespace characters

javascript regex whitespace

13,112

Solution 1

HTML != Javascript. Javascript is completely literal, %20 is %20 and   is a string of characters & n b s p and ;. For character classes I consider nearly every that is RegEx in perl to be applicable in JS (you can't do named groups etc).

http://www.regular-expressions.info/javascript.html is the refernece I use.

Solution 2

A simple test:

for(var i = 0; i < 1000; i++) {
    if(String.fromCharCode(i).replace(/\s+/, "") == "") console.log(i);
}

The char codes (Chrome):

Solution 3

For Mozilla its;

 [ \f\n\r\t\v\u00A0\u2028\u2029]

(Ref)

For IE (JScript) its

[ \f\n\r\t\v]

(Ref)

Solution 4

In Firefox \s - matches a single white space character, including space, tab, form feed, line feed. Equivalent to [ \f\n\r\t\v\u00A0\u2028\u2029].

For example, /\s\w*/ matches ' bar' in "foo bar."

https://developer.mozilla.org/en/JavaScript/Guide/Regular_Expressions

Solution 5

Here's an expansion of primvdb's answer, covering the entire 16-bit space, including unicode code point values and a comparison with str.trim(). I tried to edit the answer to improve it, but my edit was rejected, so I had to post this new one.

Identify all single-byte characters which will be matched as whitespace regex \s or by String.prototype.trim():

const regexList = [];
const trimList = [];

for (let codePoint = 0; codePoint < 2 ** 16; codePoint += 1) {
  const str = String.fromCodePoint(codePoint);
  const unicode = codePoint.toString(16).padStart(4, '0');

  if (str.replace(/\s/, '') === '') regexList.push([codePoint, unicode]);
  if (str.trim() === '') trimList.push([codePoint, unicode]);
}

const identical = JSON.stringify(regexList) === JSON.stringify(trimList);
const list = regexList.reduce((str, [codePoint, unicode]) => `${str}${unicode} ${codePoint}\n`, '');

console.log({identical});
console.log(list);

The list (in V8):

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Author by

beatgammit

I write lots of code for fun and pay. Go, Rust, and Javascript are my specialties, though I'm confident in Python, Java, C#, C++, and C, with passing interest in a few other languages.

Updated on June 13, 2022

Comments

beatgammit almost 2 years

I have done some searching, but I couldn't find a definitive list of whitespace characters included in the \s in JavaScript's regex.

I know that I can rely on space, line feed, carriage return, and tab as being whitespace, but I thought that since JavaScript was traditionally only for the browser, maybe URL encoded whitespace and things like   and %20 would be supported as well.

What exactly is considered by JavaScript's regex compiler? If there are differences between browsers, I only really care about webkit browsers, but it would be nice to know of any differences. Also, what about Node.js?
beatgammit about 13 years

Right, but JavaScript often runs in the browser, so I assumed that there might be some special cases.
beatgammit about 13 years

I'm marked yours as correct because you cleared up the root question. Thanks!
Alex K. about 13 years

FF looks like it does, for IE instead of \s use the class [\s\u00A0\u2028\u2029]