Question

If I do:

"A first sentence. A second sentence".match(/A\s([^\s]*)\ssentence/g)

this returns:

["A first sentence", "A second sentence"]

And if I use:

RegExp.$1

then I just get the last first parenthesis capture, so "second".

I’d like to get the array ["first","second"]. Is it possible?

Answer 1

You’d need to run it in a loop, and build the collection.

var str = "A first sentence. A second sentence",
    regex = /A\s([^\s]*)\ssentence/g,
    result = [],
    match;

while (match = regex.exec(str)) {
    result.push(match[1]);
}

console.log(result);

Because the regex is g global, it remembers the position of the last match, and starts from there the next time the regex is used. So the loop will continue until no more matches are found.

Inside the loop, we just add the subgroup to the result Array.

---

Some people like to use .replace for this purpose.

var str = "A first sentence. A second sentence",
    regex = /A\s([^\s]*)\ssentence/g,
    result = [];

str.replace(regex, function(str, g1) {
    result.push(g1);
});

console.log(result);

We’re not actually doing a string replacement, but rather are just taking advantage of the fact that it repeats the search until no more matches are found.