how to detect and get url on string javascript

You input has double :: after http. Not sure if it intentional. If it is then use:

var matches = string.match(/\bhttps?::\/\/\S+/gi);

If only one : is needed then use:

var matches = string.match(/\bhttps?:\/\/\S+/gi);

RegEx Demo

const string = "hei dude, check this link http:://google.com and http:://youtube.com"
const matches = string.match(/\bhttp?::\/\/\S+/gi);
console.log(matches);