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. You probably know the string method split()
.
Call it on a string, define a separator and receive an array of its substrings. Easy peasy!
"Hello party people!".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.
// Split the string on "-" and "_"
"Hello_party-people!".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 returned 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 parentheses ((
and )
), the matching values are included in the result. 😲
// Split the string on "-" and "_"
// but include the separator in the result
"Hello_party-people!".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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