regex: replace dynamically a searched word

Question

I want to replace file:///Downloads/project by a another word like a github link :

const string = 'file:///Downloads/project/users/controllers/users/controller.js';

I tried working with .replace a world by a world but i got in the problem that file:///Downloads/project is a dynamic value that may change from time to time.

string.replace(/file\:\/\/Downloads\/project\/users\/controller.js/gi, 'https://gitlab.com')

So i want to search for the word project and replace from it backward by another path or word

Answer 1

To achieve expected result, use below option of using indexOf and substr and finally replacing with gitlab url

1. Get index of project
2. Get string from 0 to index of project
3. Replace string from step 2 with gitlab using replace option

 const string = 'file:///Downloads/project/users/controllers/users/controller.js'; const index = string.indexOf('project') console.log(string.replace(string.substr(0, index), 'https://gitlab.com/')) 

codepen - https://codepen.io/nagasai/pen/qvjdEa?editors=1010

Answer 2

Using regex you can match the first group which includes /project and replace the first parenthesized capture group with your https://gitlab.com . Here p1 denotes first parenthesized capture group and p2 denotes second parenthesized capture group.

 const str = 'file:///Downloads/project/users/controllers/users/controller.js'; const res = str.replace(/^(.|\\/)+\\w*project(.+)*/gi, function(match, p1, p2) { return 'https://gitlab.com' + p2; }); console.log(res); 

Answer 3

you don't need a regex for that

 const string = 'file:///Downloads/project/users/controllers/users/controller.js', yourValue = "file:///Downloads/project/", res = string.replace(yourValue, "https://gitlab.com/") console.log(res) 

Answer 4

'https://gitlab.com/' + string.substr(string.indexOf('project'))

---

First find the position of 'project' in your string

string.indexOf('project')

then get a substring from that position to the end of the string (substr goes till the end when no second arg is provided)

string.substring(indexOfProject)

then concat it with '+'. Note that the url ends with '/' because your string will begin with 'p'.

'https://gitlab.com/' + extractedString