Split a string based on substring delimiter, keeping the delimiter in the result

Question

I'd like to be able to split up a string based on a substring delimiter, starting the split before the first character of the delimiter substring. Currently:

var string = "choc: 123 choc: 328 choc: 129";
string.split("choc");

Will give me ["", ":123 ", ": 328", ": 129"], but I am looking to get ["choc: 123 ", "choc: 328", "choc: 129"], instead.

Possible duplicate of [Split String in Javascript but keep delimiter /](https://stackoverflow.com/questions/36464953/split-string-in-javascript-but-keep-delimiter) and [Javascript split string by another string and include that another string that was used to split it into result](https://stackoverflow.com/questions/45109097) and [Split string into array without deleting delimiter?](https://stackoverflow.com/questions/24503827) and [JS string.split() without removing the delimiters](https://stackoverflow.com/questions/4514144) — adiga, Feb 13 '19 at 13:08
Why not match instead of split to begin with in such a case? (Assuming the discrepancy between `choc: 123 ` and `choc: 328`, one with trailing slash, the other without, is just negligence during posting, and not the actual requirement.) — 04FS, Feb 13 '19 at 13:14

score 4 · Accepted Answer · answered Feb 13 '19 at 13:09

4

You could take a positive lookahead.

var string = "choc: 123 choc: 328 choc: 129";
console.log(string.split(/(?=choc)/));

answered Feb 13 '19 at 13:09

Nina Scholz

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score 0 · Answer 2 · answered Feb 13 '19 at 13:14

You can do it with a positive lookahead as @Nina Scholz said, and add \s* before the lookahead to remove any leading space before choc:

const string = 'choc: 123 choc: 328 choc: 129';
const result = string.split(/\s*(?=choc)/);

console.log(result);

Split a string based on substring delimiter, keeping the delimiter in the result

2 Answers2