Regex to get everything between and including curly braces only if a given condition

Question

Hello I am trying to create a regex which will grab everything between and including the curly braces only if the string between braces starts with # and if there is a \n after the closing curly brace }

I have this following string as an example -

## Markdown Syntax {#markdown-syntax}\n\n (lorem ipsum test).\n\n## Headers {#headers}\n\n function HelloCodeTitle(props) {return <h1>Hello, {props.name}</h1>; } {2}

In this example, I am looking to extract {#markdown-syntax} and {#headers} from the above string and replace them with empty space ''

I have written this regex but this is also grabbing {return <h1>Hello, {props.name} and {2} which I do not want. I am only looking to grab {#markdown-syntax} and {#headers} (including braces) as the string between braces starts with # and there is a \n after the closing curly brace }

Answer 1

Use match() with the appropriate pattern:

 var input = "## Markdown Syntax {#markdown-syntax}\n\n (lorem ipsum test).\n\n## Headers {#headers}\n\n function HelloCodeTitle(props) {return <h1>Hello, {props.name}</h1>; } {2}"; var tags = input.match(/\{#.*?\}(?=\n)/g, input); console.log(tags);

The regex pattern used above says to:

\{      match opening {
#       match #
.*?     match all content up the first
\}      closing }
(?=\n)  assert that what follows is a newline character

If you want to remove these tags, then use replace with the same pattern:

 var input = "## Markdown Syntax {#markdown-syntax}\n\n (lorem ipsum test).\n\n## Headers {#headers}\n\n function HelloCodeTitle(props) {return <h1>Hello, {props.name}</h1>; } {2}"; var output = input.replace(/\s*\{#.*?\}(?=\n)/g, " ").trim(); console.log(output);