You can simply use replaceAll :

string_with_backslash.replaceAll('\\','')

This will remove backslashes except for the new line slash(\n).

EDIT: ignore this. The correct answer is provided in the comment by @T.J. Crowder.

It appears you're receiving JSON data via an API. The data will arrive as a STRING and you can parse it to get an OBJECT.

const myJSONData = JSON.parse(response.data)

Can you find out how the server "encodes" the data being sent to you? Understanding what is done in that step is critical to being able to "decode" the data back to the original state. The server is probably stringifying the entire structure, but they may be calling encodeURIComponent or doing other processing that you need to be aware of.

You can use regular expression and replace to remove the backlash and \n from your string.

use the following code :

let a = "<p class=\"nameclass\"> \n Rakesh </p>";
let n = a.replace(/\n/,"")

output : '<p class="nameclass">  Rakesh </p>'

replace will not do changes in the original string, so store the value in a different string.