Get the Part After First Occurrence in a String in JavaScript or Node.js

JavaScript’s stdlib for strings contains dozens of methods. These methods are useful in a lot of situations. Yet, there are use cases where a method doesn’t exist in the stdlib.

For example, there’s no method to retrieve a part of a string after a character or character sequence. For this case, you need to build your own utility method using the existing functionality.

That’s what this tutorial shows you: how to retrieve the part of a string after the first occurrence of a given delimiter.

Node.js Series Overview

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  2. Remove All Whitespace From a String in JavaScript
  3. Generate a Random ID or String in Node.js or JavaScript
  4. Remove Extra Spaces From a String in JavaScript or Node.js
  5. Remove Numbers From a String in JavaScript or Node.js
  6. Get the Part Before a Character in a String in JavaScript or Node.js
  7. Get the Part After a Character in a String in JavaScript or Node.js
  8. How to Check if a Value is a String in JavaScript or Node.js
  9. Check If a String Includes All Strings in JavaScript/Node.js/TypeScript
  10. Check if a Value is a String in JavaScript and Node.js
  11. Limit and Truncate a String to a Given Length in JavaScript and Node.js
  12. Split a String into a List of Characters in JavaScript and Node.js
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  15. Split a String into a List of Lines in JavaScript or Node.js
  16. Split a String into a List of Words in JavaScript or Node.js
  17. Detect if a String is in camelCase Format in Javascript or Node.js
  18. Check If a String Is in Lowercase in JavaScript or Node.js
  19. Check If a String is in Uppercase in JavaScript or Node.js
  20. Get the Part After First Occurrence in a String in JavaScript or Node.js
  21. Get the Part Before First Occurrence in a String in JavaScript or Node.js
  22. Get the Part Before Last Occurrence in a String in JavaScript or Node.js
  23. Get the Part After Last Occurrence in a String in JavaScript or Node.js
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  26. Append Characters or Words to a String in JavaScript or Node.js
  27. Check if a String is Empty in JavaScript or Node.js
  28. Ensure a String Ends with a Given Character in JavaScript or Node.js
  29. Left-Trim Characters Off a String in JavaScript or Node.js
  30. Right-Trim Characters Off a String in JavaScript or Node.js
  31. Lowercase the First Character of a String in JavaScript or Node.js
  32. Uppercase the First Character of a String in JavaScript or Node.js
  33. Prepend Characters or Words to a String in JavaScript or Node.js
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  35. Convert a String to Buffer
  36. Prevent Line Breaks in String Template Literals
  37. How to Implement a Custom `toString` Method (Coming soon)
  38. What Is `Symbol.toStringTag` and How to Use It (Coming soon)

Retrieve the String After a Delimiter

When interacting with string values you may want to retrieve a portion of the string after a given character sequence. This “after” method isn’t available in JavaScript directly and we’re building it ourselves.

JavaScript comes with the String#split method allowing you to split a string at a given delimiter. The split method returns an ordered array of substrings.

The after utility method should return the remainder of a string after matching the occurrence of a character sequence. That means you want to return everything from the array of substrings except the first item.

In case the divided array of substrings contains only one item, it means the delimiter value wasn’t found and you’re returning the original string value.

Here’s a sample after utility function returning the remainder of a string after the first occurrence of a given character:

/**
 * Returns the portion of the string after the first occurrence of the given `delimiter`.
 *
 * @param {String} value
 * @param {String} delimiter
 *
 * @returns {String}
 */
function after (value, delimiter) {  
  value = value || ''

  if (value === '') {
    return value
  }

  const substrings = this.split(delimiter)

  return substrings.length === 1
    ? this // delimiter is not part of the string
    : substrings.slice(1).join(delimiter)
}

Then you can use the after function like this:

after('Future Studio is an awesome island', 'is')  
// ' an awesome island'

after('Future Studio is an awesome island', 'great')  
// 'Future Studio is an awesome island'

after('Future Studio')  
// 'Future Studio'

Use the @supercharge/strings Package

I’m the maintainer of the @supercharge/strings package providing convenient string utilities. It provides a useful Str#after method returning the remainder of the string after the first occurrence of a given character or character sequence:

const Str = require('@supercharge/strings')

Str('Future Studio is an awesome island').after('is')  
// ' an awesome island'

Str('Future Studio is an awesome island').after('great')  
// 'Future Studio is an awesome island'

Str('Future Studio').after()  
// 'Future Studio'

That’s it!


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