Using Regular Expressions to Extract Strings After a Specific String [JavaScript Edition]

Tadashi Shigeoka ·  Fri, August 4, 2017

I wrote JavaScript code that uses regular expressions to extract strings after a specific string, so I’d like to introduce it.

RegExp 正規表現

Using Regexper, a site that visualizes regular expressions,

/Email address: (.+?)(\\r\
|\\r|\
)/

When this regular expression is visualized, it looks like this:

Example  | regexper.com

Below is JavaScript sample code for a regular expression that extracts strings after a specific string.

var text = [
  'Full name: Satoshi Nakamoto', 
  'Email address: [email protected]',
  'Coutry: Japan',
].join('\
');

var regExp = /Email address: (.+?)(\\r\
|\\r|\
)/;
var results = text.match(regExp);
// [ 'Email address: [email protected]\
',
//  '[email protected]',
//  '\
',
//  index: 28,
//  input: 'Full name: Satoshi Nakamoto\
Email address: [email protected]\
Coutry: Japan' ]

var email = (results && results[1]) ? results[1] : '';
// '[email protected]'

Personally, I’m not good with regular expressions, so I save these practical patterns as articles and search this site to use them when needed.

That’s all from the Gemba.