CODEWITHSUNDEEP
javascriptregex
Ace
Ace

Reputation: 1146

Does JavaScript support composite regular expressions?

For example, if I want to match ips, can I break it up like so:

const octet = /\d{1,3}/;
const ip = /{octet}\.{octet}\.{octet}\.{octet}/;

Upvotes: 3

Views: 287

Answers (2)

Namaskar
Namaskar

Reputation: 2119

With an already declared regular expression literal, you can use its source property to get the version without the enclosing tags. Using template literals inside a new RegExp constructor, create your new expression.

const octet = /\d{1,3}/;
const octetSource = octet.source;
const ip = new RegExp(`^${octetSource}\\.${octetSource}\\.${octetSource}\\.${octetSource}$`);

Upvotes: 6

Keith
Keith

Reputation: 24191

You could mix using new RegExp() and template literals to do it similar.

Below is an example.

const octet = /\d{1,3}/;
const octetS = octet.source;
const ip = new RegExp(
  `^${octetS}\\.${octetS}\\.${octetS}\\.${octetS}$`);

const ips = [
  '127.0.0.1',
  '10.0.2',
  '12.10.2.5',
  '12'];
  
for (const checkip of ips)
  console.log(`IP: ${checkip} = ${ip.test(checkip)}`);

Upvotes: 8

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