Regex: How to create an array of objects from all matches in javascript?

Question

I'm trying to get a string input like this:

{p}This is a paragraph{/p} {img}(path/to/image) {p}Another paragraph{/p}

To return an array of objects like this

[
  {"txt" : "This is a paragraph" },
  {"img" : "path/to/image"},
  {"txt" : "Another paragraph"}
]

I need the array to be indexed by the order they are found – i.e. in the example above the first paragraph gets index 0, image gets index 1 and so forth.

I can get the strings great with the code below, but I am unsure how to modify it to loop through the entire string and put together the object. So any pointers would be greatly appreciated

var p = /{p}(.*){\/p}/gmi;
var i = /{img}\((.*)\)/gmi;

var test = "{p} This is a paragraph {/p} {img}(text)";


function returnJson(test) {
  var ps = p.exec(test);
  var im = i.exec(test)
  var arr = [];
  if (ps.length > 1) {
    arr.push({"txt" : ps[1]})
  } 
  if (im.length > 1) {
    arr.push({"img" : im[1]})
  }
  return arr;
}

I was thinking of doing a recursive function, where I replace the found matches with the string. But then I am unsure of how to get the array in the order they were found. Any tips greatly appreciated.

I will have one or two more elements – most likely headings and links that will be marked in a similar fashion. — user2868900
– user2868900, Commented Mar 2, 2019 at 14:01
Yes, i was thinking {h}Heading{/h} and {a}Link Text{/a}(url). I am setting the markup of the strings myself, so I'm very flexible when it comes to altering the structure. — user2868900
– user2868900, Commented Mar 2, 2019 at 14:05
And will they ever be nested? Or will links always be siblings to paragraphs instead of children of them? — Sean
– Sean, Commented Mar 2, 2019 at 14:11

adiga · Accepted Answer · 2019-03-02 14:26:36Z

5

You could use this regex

/{(\w+)}([^{]+)(?:{\/\1})?/g

And create an array using exec like this:

let str = "{p}This is a paragraph{/p} {img}(path/to/image) {p}Another paragraph{/p}";

let regex = /{(\w+)}([^{]+)(?:{\/\1})?/g;
let match;
let matches = [];

while (match = regex.exec(str)) {
    if(match[1] == "p")
      matches.push({ txt: match[2] })
    else
      matches.push({ [match[1]]: match[2]})
}

console.log(matches)

{(\w+)} gets the tag name to a capturing group
([^{]+) gets the content to another capturing group
(?:{\/\1})? optionally matches the closing tag. (\1 refers to the first capturing group)

edited Mar 2, 2019 at 14:26

answered Mar 2, 2019 at 14:20

adiga

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3 Comments

Sean Over a year ago

Very close! There's parens around the image path that need to be removed, and a trailing space.

user2868900 Over a year ago

Thank you! Clever idea with the while-loop and using the different capture groups to add to the array. I modified the expression to {(\w+)}(?:\()?([^{[\)]+)(?:\))?(?:{\/\1})? to exclude a leading parenthesis and not match the ending parenthesis. This looks like it should work? I am new to these more complex regex patterns, so sorry if it is obvious

adiga Over a year ago

@user2868900 I didn't see the parenthesis bit. That should work: regex101.com/r/TMRVG8/1

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