String interpolation in Typescript, replacing ‘placeholders’ with variables

Use a template string which are much better than String.Format in my opinion as they do not suffer from poor indexing (wrong placeholder) issues:

var text = "blah blah";
var strTest = `This is a ${text}`;
console.log(strTest);

If I do not know the name of the variables I need to pass in??

Then wrap in a function e.g.

const gen = (text) => `This is a ${text}`;