How to parse string with {{}}

Question

I have a string

var str = "{{a}} {{b}} aaa";

I want to split the string with {{}}. So, my expected result is

array = ["a", "b"]

Update:

As another case, given

var str1 = "{{a {{b}}}}",
    str2 = "{{{a}}}";

The result should be

var arr1 = ["b"],
    arr2 = ["a"];

How do you want to handle cases like `'{{a {{b}}}}'` and `'{{{a}}}'`? — Chris Hunt, Dec 20 '16 at 03:19
in @ChrisHunt case, the my result will be `["a {{b}}", "{a}"]` — Vu Le Anh, Dec 20 '16 at 03:23
@TedHopp OP says they want to split the string. It does appear they don't want to split it, but instead tease out certain portions of it, ala template tags or something. I'm asking for clarification. — ceejayoz, Dec 20 '16 at 03:23
Also, how do you want to handle something like `"{{ab}c}}"`? — Ted Hopp, Dec 20 '16 at 03:24
You can use `/{{([^}]*?)}}/g` Here's [**Demo**](https://jsfiddle.net/tusharj/zgqwqgea/) — Tushar, Dec 20 '16 at 03:24
@Tushar, this is not a duplicate, the answer on the other post does not work in the cases specified above. — Chris Hunt, Dec 20 '16 at 03:28
If `'{{a {{b}}}}` is supposed to yield `'a {{b}}'`, you aren't going to do that with a regex, at least if you want to handle arbitrarily deep nesting of `{{}}` pairs. That's more than a finite state automaton can handle. See [this thread](http://stackoverflow.com/questions/133601/can-regular-expressions-be-used-to-match-nested-patterns), for example. — Ted Hopp, Dec 20 '16 at 03:29
@VuLeAnh I've reopened the question. Please [edit] the question to add those details. — Tushar, Dec 20 '16 at 03:30
@VuLeAnh what criteria do you have in mind that makes `'{{{a}}}'` go to `['{a}']` but `'{{a}} {{b}}'` go to `['a', 'b']`? There's some ambiguity there. — Chris Hunt, Dec 20 '16 at 03:42
The problem is that `'a}} {{b'` is between `{{` and `}}` in my second example but that's not what you want to happen. — Chris Hunt, Dec 20 '16 at 03:46
@ChrisHunt Thanks for clear my mistake. So, the result in your case should be `['b']` and `['a']` — Vu Le Anh, Dec 20 '16 at 03:50
Another clarification request. How do you want to handle something like `"{a {{b}}}"`? — Ted Hopp, Dec 20 '16 at 03:59

Alexander O'Mara · Accepted Answer · 2016-12-20T03:47:12.777

3

One option would be to match them all, then extract the contents.

var units = [
    "{{a}} {{b}} aaa",
    "{{a {{b}}}}",
    "{{{a}}};"
];
units.forEach(function(str) {
    var matched = str.match(/{{([^}]*[^{]*)}}/g).map(function(s) {
        return s.substring(2, s.length - 2)
    });
    console.log(str, '=');
    console.log(matched);
});

edited Dec 20 '16 at 03:47

answered Dec 20 '16 at 03:23

Alexander O'Mara

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@Tushar Yep. Done! – Alexander O'Mara Dec 20 '16 at 03:47
Cool. Here's [Demo on RegEx101](https://www.regex101.com/r/GdRgVN/3). Please add explanation of the regex as well. – Tushar Dec 20 '16 at 03:48
check with `"{{a {{b}} {{c}}}}"` – Pranav C Balan Dec 20 '16 at 03:49
@PranavCBalan Blarg. Depending on what it should output, maybe not perfect. – Alexander O'Mara Dec 20 '16 at 03:50
@Tushar : I think he needs `a {{b}} {{c}}` , regex is not a correct solution for this.... – Pranav C Balan Dec 20 '16 at 03:51
Sorry all for my confusing question because I do not imagine all cases. – Vu Le Anh Dec 20 '16 at 03:57
Sorry all for my confusing question. I did not imagine all cases @AlexanderO'Mara Could you please update your answer as before – Vu Le Anh Dec 20 '16 at 04:00
@VuLeAnh How so? I'm not sure regex can solve these more-complicated balancing issues. – Alexander O'Mara Dec 20 '16 at 04:01
@AlexanderO'Mara I think my expectation it is more complicated. I accepted your before answer `var matched = str.match(/{{[^}]}}/g).map(function(s) { return s.substring(2, s.length - 2) });` – Vu Le Anh Dec 20 '16 at 04:08

l'L'l · Answer 2 · 2016-12-20T04:38:53.927

0

As mentioned there might not be a best way to cover every scenario, but split could be used like:

var str1 = "{{a}} {{b}} aaa", str2 = "{{a {{b}}}}", str3 = "{{{a}}};"

var splits = str1.split(/[^{][^.][^}]|[{}]/).filter(Boolean);
console.log(splits);

Results:

Array [ "a", "b" ]
Array [ "b" ]
Array [ "a" ]

Examples:

https://jsfiddle.net/gsL46bg7

edited Dec 20 '16 at 04:38

answered Dec 20 '16 at 04:24

l'L'l

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How to parse string with {{}}

2 Answers2