Split a string by whitespace, keeping quoted segments, allowing escaped quotes

user_451480 0
Viewed 12517

I currently have this regular expression to split strings by all whitespace, unless it's in a quoted segment:

keywords = 'pop rock "hard rock"';
keywords = keywords.match(/\w+|"[^"]+"/g);
console.log(keywords); // [pop, rock, "hard rock"]

However, I also want it to be possible to have quotes in keywords, like this:

keywords = 'pop rock "hard rock" "\"dream\" pop"';

This should return 

[pop, rock, "hard rock", "\"dream\" pop"]

What's the easiest way to achieve this?

javascript regex
4 Answers

ES6 solution supporting:

  • Split by space except for inside quotes
  • Removing quotes but not for backslash escaped quotes
  • Escaped quote become quote
  • Can put quotes anywhere

Code:

keywords.match(/\\?.|^$/g).reduce((p, c) => {
        if(c === '"'){
            p.quote ^= 1;
        }else if(!p.quote && c === ' '){
            p.a.push('');
        }else{
            p.a[p.a.length-1] += c.replace(/\\(.)/,"$1");
        }
        return  p;
    }, {a: ['']}).a

Output:

[ 'pop', 'rock', 'hard rock', '"dream" pop' ]
user_13092180

If Kobi's answer works well for the example string, it doesn't when there are more than one successive escape characters (backslashes) between quotes as Tim Pietzcker noticed it in comments. To handle these cases, the pattern can be written like this (for the match method):

(?=\S)[^"\s]*(?:"[^\\"]*(?:\\[\s\S][^\\"]*)*"[^"\s]*)*

demo

Where (?=\S) ensures there's at least one non-white-space character at the current position since the following, that describes all allowed sub-strings (including whitespaces between quotes) is totally optional.

Details:

(?=\S)   # followed by a non-whitespace
[^"\s]*  #"# zero or more characters that aren't a quote or a whitespace
(?: # when a quoted substring occurs:
    "       #"# opening quote
    [^\\"]* #"# zero or more characters that aren't a quote or a backslash
    (?: # when a backslash is encountered:
        \\ [\s\S] # an escaped character (including a quote or a backslash)
        [^\\"]* #"#
    )*
    "         #"# closing quote
    [^"\s]*   #"#
)*
user_22550890
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