I have the following Regex code that's taking a long time (30+ seconds) to validate large URLS:
let validReg = new RegExp('^(https?:\\/\\/)?'+ // protocol
'((([a-z\\d]([a-z\\d-]*[a-z\\d])*)\\.)+[a-z]{2,}|'+ // domain name
'((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address
'(\\:\\d+)?(\\/[-a-z\\d%_.~+]*)*'+ // port and path
'(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string
'(\\#[-a-z\\d_]*)?$','i');
let isValid = validReg.test(component.repository_url);
How can I change this code to validate the same Regex more efficiently?
You need to refactor the part where you match hyphen separated word chars: [a-z\\d]([a-z\\d-]*[a-z\\d])* => [a-z\\d]+(?:-+[a-z\\d]+)*.
Also, note you do not need to escape / chars, they are not special regex metacharacters, and you are not using a regex literal.
You may use
let validReg = new RegExp('^(https?://)?'+ // protocol
'((([a-z\\d]+(?:-+[a-z\\d]+)*)\\.)+[a-z]{2,}|'+ // domain name
'((\\d{1,3}\\.){3}\\d{1,3}))'+ // OR ip (v4) address
'(:\\d+)?(/[-a-z\\d%_.~+]*)*'+ // port and path
'(\\?[;&a-z\\d%_.~+=-]*)?'+ // query string
'(#[-a-z\\d_]*)?$','i');
let isValid = validReg.test(component.repository_url);