How can I avoid control character interpretation in Javascript template string interpolation?

Question

I have a string variable containing a control character (newline). I want to output that variable but with the control character as its literal representation and not interpreted:

console.log(`Using "${nl}" as newline`)

where the nl variable may contain one of \n, \r, or \r\n. The output of this is of course

Using
as newline

but it should be e.g.

Using "\r\n" as newline

I guess I somehow need to construct a string like this

console.log('Using "\\r\\n" as newline')

So I've been trying to escape the backslashes in nl by prepending another backslash using nl.replace() but that doesn't seem to work because the nl variable doesn't actually contain any backslash characters.

Is there a way to do this generically, i.e. without coding explicitly for \n, \r, and \r\n?

Answer 1

You could remove the double quotes, and use JSON.stringify which also produces those quotes, and which encodes newline characters (and more, such as TAB, BS, FF, and escapes double quote and backslash):

let nl = "\r\n";
console.log(`Using ${JSON.stringify(nl)} as newline`);

// Or with a newline in a template literal:

nl = `
`;
console.log(`Using ${JSON.stringify(nl)} as newline`);