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RegExp

Medium

In plain terms

Regular expressions match patterns in text. Create with /pattern/flags or new RegExp(). Methods: test, exec. String methods: match, replace, search, split. Flags: g, i, m.

What you need to know

  • •/pattern/flags
  • •test, exec, match, replace
  • •g global, i ignore case

Try it yourself

Copy the code below and run it in your browser console or a code editor:

const re = /\d+/g;
're 123 abc 456'.match(re);  // ['123', '456']

/hello/i.test('Hello World');  // true (i = ignore case)

const email = /^[^@]+@[^@]+\.[^@]+$/;
email.test('a@b.com');  // true

'hello'.replace(/l/g, 'L');  // "heLLo"

Learn more

Dive deeper with these trusted resources:

MDNjavascript.infoTutorialsPointW3Schools