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RegEx to extract all matches from string using RegExp.exec

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How do I find all matches in regex?

The method str. match(regexp) finds matches for regexp in the string str . If the regexp has flag g , then it returns an array of all matches as strings, without capturing groups and other details. If there are no matches, no matter if there's flag g or not, null is returned.

What does regex exec return?

JavaScript RegExp exec() The exec() method tests for a match in a string. If it finds a match, it returns a result array, otherwise it returns null.

What does regex (? S match?

i) makes the regex case insensitive. (? s) for "single line mode" makes the dot match all characters, including line breaks.

Does empty regex match everything?

An empty regular expression matches everything.


Continue calling re.exec(s) in a loop to obtain all the matches:

var re = /\s*([^[:]+):\"([^"]+)"/g;
var s = '[description:"aoeu" uuid:"123sth"]';
var m;

do {
    m = re.exec(s);
    if (m) {
        console.log(m[1], m[2]);
    }
} while (m);

Try it with this JSFiddle: https://jsfiddle.net/7yS2V/


str.match(pattern), if pattern has the global flag g, will return all the matches as an array.

For example:

const str = 'All of us except @Emran, @Raju and @Noman were there';
console.log(
  str.match(/@\w*/g)
);
// Will log ["@Emran", "@Raju", "@Noman"]

To loop through all matches, you can use the replace function:

var re = /\s*([^[:]+):\"([^"]+)"/g;
var s = '[description:"aoeu" uuid:"123sth"]';

s.replace(re, function(match, g1, g2) { console.log(g1, g2); });

This is a solution

var s = '[description:"aoeu" uuid:"123sth"]';

var re = /\s*([^[:]+):\"([^"]+)"/g;
var m;
while (m = re.exec(s)) {
  console.log(m[1], m[2]);
}

This is based on lawnsea's answer, but shorter.

Notice that the `g' flag must be set to move the internal pointer forward across invocations.


str.match(/regex/g)

returns all matches as an array.

If, for some mysterious reason, you need the additional information comes with exec, as an alternative to previous answers, you could do it with a recursive function instead of a loop as follows (which also looks cooler :).

function findMatches(regex, str, matches = []) {
   const res = regex.exec(str)
   res && matches.push(res) && findMatches(regex, str, matches)
   return matches
}

// Usage
const matches = findMatches(/regex/g, str)

as stated in the comments before, it's important to have g at the end of regex definition to move the pointer forward in each execution.


We are finally beginning to see a built-in matchAll function, see here for the description and compatibility table. It looks like as of May 2020, Chrome, Edge, Firefox, and Node.js (12+) are supported but not IE, Safari, and Opera. Seems like it was drafted in December 2018 so give it some time to reach all browsers, but I trust it will get there.

The built-in matchAll function is nice because it returns an iterable. It also returns capturing groups for every match! So you can do things like

// get the letters before and after "o"
let matches = "stackoverflow".matchAll(/(\w)o(\w)/g);

for (match of matches) {
    console.log("letter before:" + match[1]);
    console.log("letter after:" + match[2]);
}

arrayOfAllMatches = [...matches]; // you can also turn the iterable into an array

It also seem like every match object uses the same format as match(). So each object is an array of the match and capturing groups, along with three additional properties index, input, and groups. So it looks like:

[<match>, <group1>, <group2>, ..., index: <match offset>, input: <original string>, groups: <named capture groups>]

For more information about matchAll there is also a Google developers page. There are also polyfills/shims available.


If you have ES9

(Meaning if your system: Chrome, Node.js, Firefox, etc supports Ecmascript 2019 or later)

Use the new yourString.matchAll( /your-regex/ ).

If you don't have ES9

If you have an older system, here's a function for easy copy and pasting

function findAll(regexPattern, sourceString) {
    let output = []
    let match
    // make sure the pattern has the global flag
    let regexPatternWithGlobal = RegExp(regexPattern,[...new Set("g"+regexPattern.flags)].join(""))
    while (match = regexPatternWithGlobal.exec(sourceString)) {
        // get rid of the string copy
        delete match.input
        // store the match data
        output.push(match)
    } 
    return output
}

example usage:

console.log(   findAll(/blah/g,'blah1 blah2')   ) 

outputs:

[ [ 'blah', index: 0 ], [ 'blah', index: 6 ] ]