String.prototype.match() (aka: the match method on strings) can allow you to switch out strings or set conditions if a string or any data is matched. It then stores that data in a new array.
First the syntax and then the explanation:
let newArray = string.match(condition);
match() method will return an array with the items being matches from a provided
Remember, when all conditions are matched, those results will be stored in a new array.
Take the following example:
const intro = "Hello Alligators, Hello Devs, how are you?" const regex = /Hello/g; const greeting = intro.match(regex);
The above will give us an array like this:
["Hello", "Hello"]. This works fine if we know the exact string we’re looking to match, but what about dynamic content or an actual use case?
Here’s a simple example that finds repeated letters in a string:
const str = 'See you later, Alligator! Not so soon baboon!'; const matches = str.match(/([a-z])\1+/gi); console.log('H' + matches.join("")); // "Heelloooo"
— Sorry to interrupt this program! 📺
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Though these are simple examples, the deeper you learn about regular expressions, the more powerful this string method becomes. The simple use of
i for insensitive case allows the match method to highlight more entries.
The match method has 3 modes…
- 1st: If the
g(global) flag is used for your RegEx, you’ll get all results stored in an array.
- 2nd: If there are no
gflag used, the first match will return an array with keys/values sharing index of the first matched expression, the full input and then the capturing groups. In other words, the same result as with using
let newYear = "Happy New Year"; let results = newYear.match(/new/i); // [ 'New', index: 6, input: 'Happy New Year', groups: undefined ]
- 3rd: If there’s no match, the method returns
null, or, with the following code, an empty array:
let results = newYear.match(regex) || ;