Get Substring between two characters using javascript

Finer points of extraction

Put string methods to work

A wealth of methods provided by JavaScript, like .substring(), .slice(), .indexOf(), and .lastIndexOf(), allow for versatile substring extractions. Here's how you finesse it for strings with distinct delimiters:

let exampleStr = 'Foo:Bar;Baz';
let startIdx = exampleStr.indexOf(':') + 1; // That extra 1 gives the ":" the slip
let endIdx = exampleStr.lastIndexOf(';');
let result = exampleStr.substring(startIdx, endIdx);
console.log(result); // voila, it's 'Bar'
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Mad for multiple occurrences

For strings flaunting multiple delimiters, loops or the .split() method can do wonders. We'll take a whirl around:

let data = 'start:content1;middle:content2;end';
let parts = data.split(';');
for (let part of parts) {
  let content = part.split(':')[1];
  console.log(content); // 'content1' and 'content2': not bad for a day's work
}
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Regex to the rescue for dynamic splitting

Fear not if delimiter characters can't make up their minds; a potent combo of .split(), regex, and .pop() will set you right:

let complexStr = 'start#content1:end|content2:stop';
let delimiterRegex = /[:#|]/g; // RegEx: For when you absolutely, positively, got to catch every delimiter in the string
let contents = complexStr.split(delimiterRegex);
contents.pop(); // Sorry, 'stop', you're not getting in
console.log(contents); // Woo-hoo, you've cracked it!
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Techniques for every string scenario

Delving into recursive extraction

For truly convoluted, recursive patterns, we go rogue with recursive functions:

function extractSubstrings(str, startChar, endChar) {
  const results = [];
  let index = 0;
  while ((index = str.indexOf(startChar, index)) !== -1) {
    let endIndex = str.indexOf(endChar, index);
    if (endIndex === -1) break;
    results.push(str.substring(index + 1, endIndex)); // Treasure hunted and bagged
    index = endIndex + 1; // On to the next hunt
  }
  return results;
}
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Show, don't tell, with alert()

Why tell when you can show? Let alert() display your substrings in all their glory during debugging:

alert('Behold the extracted substring: ' + substring);
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