Javascript - How to get a list of strings between two characters

Question

How can implement a function that returns a list of characters between two characters?

const string = "My name is <<firstname>> and I am <<age>>";

const getVariables = (string) => { 
  // How do I implement?
}

console.log(getVariables(string));  // ['firstname', 'age']

PS: I realize there are multiple answers on how to do something similar, but all of them only work for getting first instance and not all occurrences.

Regular expressions is your friend – Daniel A. White Oct 13 '22 at 11:08 — Daniel A. White, Oct 13 '22 at 11:08
Show us what you tried already. – Drishti Jain Oct 13 '22 at 11:09 — Drishti Jain, Oct 13 '22 at 11:09

score 0 · Answer 1 · answered Oct 13 '22 at 11:09

Assuming this is some kind of templating, you can proceed like this:

let format = (str, vars) => 
  str.replace(/<<(\w+)>>/g, (_, w) => vars[w]);
  
//

const tpl = "My name is <<firstname>> and I am <<age>>";

console.log(
  format(tpl, {firstname: 'Bob', age: 33})
)

Nina Scholz · Answer 2 · 2022-10-13T11:15:03.440

0

You could search for string which has the starting pattern and end pattern with look behind and look ahead.

const
    string = "My name is <<firstname>> and I am <<age>>",
    parts = string.match(/(?<=\<\<).*?(?=\>\>)/g);

console.log(parts);

edited Oct 13 '22 at 11:15

answered Oct 13 '22 at 11:09

Nina Scholz

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score 0 · Answer 3 · answered Oct 13 '22 at 11:19

You could use regex, group, matchAll and get the first group

const string = "My name is <<firstname>>, from <<place>>, and I am <<age>>"

const getVariables = string => {
  return [...string.matchAll(/<<(\w+)>>/g)].map(match => match[1])
}

console.log(getVariables(string))

Javascript - How to get a list of strings between two characters

3 Answers3