How do I test this regex in JavaScript and TypeScript?

Use regex.test(): const regex = /!\[([^\]]*)\]\(([^\s)]+)(?:\s+"([^"]+)")?\)/g; const isValid = regex.test(inputString);

What is an example of a matching and non-matching string?

A valid matching string is "![Company Logo](https://example.com/logo.png "Brand")". A non-matching string is "[Normal link](https://example.com)".

Is this regex safe from ReDoS (Catastrophic Backtracking)?

Yes, this pattern is optimized for linear execution time and safe for browser-side validation without locking up the UI thread.

HomeRegex LibraryMarkdown Image Syntax Regex

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Markdown Image Syntax Regex

Extracts alt text, image URL, and optional title from standard Markdown image tags.

Regular Expression Pattern:

/!\[([^\]]*)\]\(([^\s)]+)(?:\s+"([^"]+)")?\)/g

Valid Match Example:

![Company Logo](https://example.com/logo.png "Brand")

Invalid / Non-Match Example:

[Normal link](https://example.com)

Regex Syntax Breakdown & Explanation

•! : Image indicator exclamation mark
•\[([^\]]*)\] : Captures alt text within brackets
•\(([^\s)]+) : Captures image URL within parentheses
•(?:\s+"([^"]+)")?\) : Captures optional title quote before closing parenthesis

Implementation in Popular Languages

JavaScript / TypeScript

const regex = /!\[([^\]]*)\]\(([^\s)]+)(?:\s+"([^"]+)")?\)/g;
const isValid = regex.test("![Company Logo](https://example.com/logo.png "Brand")");
console.log(isValid); // true

Python (re)

import re

pattern = r"!\[([^\]]*)\]\(([^\s)]+)(?:\s+"([^"]+)")?\)"
match = re.match(pattern, "![Company Logo](https://example.com/logo.png "Brand")")
print(bool(match)) # True

Go (regexp)

package main
import (
  "fmt"
  "regexp"
)

func main() {
  re := regexp.MustCompile(`!\[([^\]]*)\]\(([^\s)]+)(?:\s+"([^"]+)")?\)`)
  fmt.Println(re.MatchString("![Company Logo](https://example.com/logo.png "Brand")"))
}

Frequently Asked Questions

Everything you need to know regarding specifications, syntax, and security best practices.

The regular expression pattern is /!\[([^\]]*)\]\(([^\s)]+)(?:\s+"([^"]+)")?\)/g. Extracts alt text, image URL, and optional title from standard Markdown image tags.