JavaScript是否支持复合正则表达式？

Question

例如，如果我想匹配ips，可以将其分解为：

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

Answer 1

您可以将using new RegExp()和template文字混合使用，以达到类似目的。

下面是一个例子。

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)}`);

Answer 2

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}$`);