LAST UPDATED: JUNE 25, 2021
Javascript ES11 matchAll() Function
The matchAll() is a new method of String class provided with ECMAScript 2020 which works with regular expressions. This method returns all matches for a regular expression that exists in a particular string. The matches are returned as an iterator to access them in a one-at-a-time method, or we can use a for...of loop and convert them to an array and then access it.
Syntax for matchAll():
The syntax of string.prototype.matchAll() method is given below:
string.prototype.matchAll(reg_exp)
Parameters:
-
String - This is the reference string for which matches are to be found.
-
Regexp - It is a regular expression object which includes /g flag; otherwise, it will through TypeError.
-
Return Value - The return value will be an iterator containing the matches, including the capturing groups.
Each item of the returned value will have the following properties:
-
groups - It consists of the result of the named capturing groups specified in the regular expression
-
index - The index of search where the result was found.
-
input - A copy of the search string.
Let's understand it better with the help of an example.
Example: Applying String.prototype.matchAll() method
In this example, we have demonstrated how we can find the matches using regular expression also captured the internal groups with the help of matchAll() method.
<!DOCTYPE html>
<html>
<head>
<title>ECMA Script</title>
</head>
<body>
<script>
const regexp = /t(e)(st(\d?))/g;
const str = 'test1test2';
const array = [...str.matchAll(regexp)];
console.log(array[0]);
console.log(array[1]);
</script>
</body>
</html>
Output:
Conclusion
In this article, we have explained the matchAll() method and introduced the usage of the method. Also, we have learned the following points:
-
String.prototype.matchAll() method returns an iterator that represents the matches and allows us to iterate, destructure or transform to an array when needed.
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If no matches were found, then String.prototype.matchAll() method returns a null.
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This method considers all matches, including capturing groups in simple usage.
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This method throws a TypeError while using non-global regular expression.
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After exhausting the iterator, we need to reinvoke String.prototype.matchAll to iterate once more.
