How to preserve separators in the result of String.prototype.split()
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Today, I found a tiny JavaScript gem that may come in handy in the future. You probably know the string method split()
.
Call it on a string, define a separator and receive an array of its substrings.
const string = "Hello party people!";
console.log(string.split(' '));
// Array(3) [ "Hello", "party", "people!" ]
The first function parameter, the separator, can be a string value but also a regular expression. By using a regular expression you can devide the original string dependending on different separators.
const string = "Hello_party-people!";
console.log(string.split(/[-_]/));
// Array(3) [ "Hello", "party", "people!" ]
No matter if your separator is a string value or regular expression, its value is usually not included in the resulting array. MDN states this functionality as follows:
When found, separator
is removed from the string, and the substrings are returned in an array.
But here's the JavaScript trivia: if you use a regular expression as the separator and this regular expression includes capturing paratheses ((
and )
), the matching values are included in the result. 😲
const string = "Hello_party-people!";
console.log(string.split(/([-_])/));
// Array(5) [ "Hello", "_", "party", "-", "people!" ]
I wasn't aware of this behavior, and I bet it can replace some complex regular expression logic!
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