30-seconds-of-code/snippets/startsWithSubstring.md

title, shortTitle, tags, expertise, cover, author, firstSeen

title	shortTitle	tags	expertise	cover	author	firstSeen
String starts with substring	Starts with substring	string	beginner	blog_images/boutique-home-office-3.jpg	chalarangelo	2022-07-31T05:00:00-04:00

Checks if a given string starts with a substring of another string.

• Use a for...in loop and String.prototype.slice() to get each substring of the given word, starting at the beginning.
• Use String.prototype.startsWith() to check the current substring against the text.
• Return the matching substring, if found. Otherwise, return undefined.

const startsWithSubstring = (text, word) => {
  for (let i in word) {
    const substr = word.slice(-i - 1);
    if (text.startsWith(substr)) return substr;
  }
  return undefined;
};

startsWithSubstring('/>Lorem ipsum dolor sit amet', '<br />'); // '/>'