Object-Oriented JavaScript — RegExp

JavaScript is partly an object-oriented language.

To learn JavaScript, we got to learn the object-oriented parts of JavaScript.

In this article, we’ll look at the RegExp object.

RegExp

The RegExp constructor lets us search and manipulate text.

JavaScript uses the Perl 5 syntax for defining regex.

A regex consists of a pattern to use and match the text.

It can optionally contain zero or more modifiers to provide more instructions on how the pattern should be used.

For instance, we can use the RegExp constructor by writing:

const re = new RegExp("c.*t");

We have a regex that matches a word with some letters in between c and t .

. means any character.

* means preceding whatever comes after.

We can add some modifiers called flags to change the regex.

Some flags include:

• g for global.
• i for ignoring case
• m for multiline

So if we have:

const re = new RegExp("c.*t", 'gmi');

We can check that it does global match with the global property.

So re.global should return true .

The property can’t be set, so assigning a value to it won’t change the value.

RegExp Methods

RegExp instances have some methods.

They include the test and exec method.

test checks whether a string matches the regex pattern.

And exec returns the string the matches the regex.

We can call test by running;

/c.*t/.test("CoffeeScript");

then we get false .

But we call:

/c.*t/i.test("CoffeeScript");

then we get true because of the case-insensitive match.

To call exec , we can write:

/c.*t/i.exec("CoffeesScript")[0];

Then we get:

"CoffeesScript"

#web-development #javascript #regexp #programming #developer

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Dependencies resolved.
===============================================================================
 Package           Architecture  Version               Repository         Size
===============================================================================
Removing:
 sendmail          x86_64        8.15.2-32.el8         @AppStream        2.4 M
Removing unused dependencies:
 cyrus-sasl        x86_64        2.1.27-1.el8          @BaseOS           160 k
 procmail          x86_64        3.22-47.el8           @AppStream        369 k

Transaction Summary
===============================================================================
Remove  3 Packages

Freed space: 2.9 M
Is this ok [y/N]: y

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