Skip to main content
Showing results for 
Search instead for 
Did you mean: 

Find everything you need to get certified on Fabric—skills challenges, live sessions, exam prep, role guidance, and more. Get started

Not applicable

Create a mutable global variable in M language

Hi, community, 

I'm working on a custom connector that needs to authenticate before data representation is done, and to do this I don't want to hardcode the auth credentials in my source code. 


So, I declared a global list variable named


config = {"a"};



and in the shared MyCustomConnector.Contents function, I'm doing a List.ReplaceValue on item "a" in the list above.


shared MyCustomConnector.Contents = (BaseUrl as text, ClientId as text) => 
List.ReplaceValue(config, "a", BaseUrl, Replacer.ReplaceText);



so in my StartLogin function, I can just call the config by index like this.


//Start Login
StartLogin = (resourceUrl, state, display) =>

        AuthorizeUrl ="https://"&Text.From(config{0})&"/oauth/authorize?" & Uri.BuildQueryString(
                client_id = "11",
                state = state,
                redirect_uri = redirect_uri
            LoginUri = AuthorizeUrl,
            CallbackUri = redirect_uri,
            WindowHeight = windowHeight,
            WindowWidth = windowWidth,
            Context = null



But it appears that, the List.ReplaceValue is not being executed because whenever I try to set credential for authentication, "a" is being passed into the URL. 


Any help will be much appreciated

Super User
Super User

Please read Ben Gribaudo's primer again.


Have a look at the meta data section too.

Helpful resources

Europe Fabric Conference

Europe’s largest Microsoft Fabric Community Conference

Join the community in Stockholm for expert Microsoft Fabric learning including a very exciting keynote from Arun Ulag, Corporate Vice President, Azure Data.

July 2024 Power BI Update

Power BI Monthly Update - July 2024

Check out the July 2024 Power BI update to learn about new features.

July Newsletter

Fabric Community Update - July 2024

Find out what's new and trending in the Fabric Community.

Top Solution Authors
Top Kudoed Authors