Javascript single backslash in string variable not working

Question

I am sending a string variable from spring boot controller to JavaScript and my string is basically a file path with single backslash. I am reading the path in JavaScript but it is ready single backslash as a escape character or something.

<script type="text/javascript">
    var path = "S:\\CD\2020\ABCDEF"
    alert(path)
</script>

The output I am getting is S:\CD‚0ABCDEF in the alert

I want "S:\CD\2020\ABCDEF"

dave · Answer 1 · 2021-08-03T16:04:53.653

1

You need to do

var path = "S:\\CD\\2020\\ABCDEF"

a backslash is an escape character so you need to escape the backslash.

If you don't control it, try to use String.raw like so:

alert(String.raw`S:\\CD\2020\ABCDEF`)

edited Aug 03 '21 at 16:04

answered Aug 03 '21 at 15:59

dave

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I am getting this variable from spring boot controller and I have no control over this variable. I cant directly change it. – Mutahir Kiani Aug 03 '21 at 16:01
You could try using `String.raw`, see edit – dave Aug 03 '21 at 16:05
is there any way to use replace function and replace single backslash with double backslash? – Mutahir Kiani Aug 03 '21 at 16:05
The issue is that the string itself doesn't actually have the backslash once it's in the variable, you need to get at it *before* it "becomes" a variable – dave Aug 03 '21 at 16:06
String.raw also does not work, now its now showing the alert – Mutahir Kiani Aug 03 '21 at 16:12

lejlun · Answer 2 · 2021-08-03T16:18:43.287

1

In JavaScript \ is an escape character used to denote the beginning of special sequences.

These sequences include \n, \t and even Unicode characters. When you want to use the \ character on its own, write two like this \\.

So in your case:

We can use String.raw to stop JavaScript from parsing escape sequences.
And also .replaceAll to change all occurrences of the \\ sequence.

var path = String.raw`S:\\CD\2020\ABCDEF`

let singular = (String.raw`\a`).slice(0, 1)
let double = String.raw`\\`

path = path.replaceAll(double, singular)

alert(path)

As a function:

function getString() {
   return String.raw `S:\\CD\2020\ABCDEF`
} // This function can be replaced with the function you are using to get the path from the user.

function replaceEscapes(rawString) {
  let singular = (String.raw `\a`).slice(0, 1)
  let double = String.raw `\\`

  return rawString.replaceAll(double, singular)
}

alert(
  replaceEscapes(getString())
)

edited Aug 03 '21 at 16:18

answered Aug 03 '21 at 16:00

lejlun

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I am getting this variable from spring boot controller and I have no control over this variable. I cant directly change it. – Mutahir Kiani Aug 03 '21 at 16:03
is there any way to use replace function and replace single backslash with double backslash? – Mutahir Kiani Aug 03 '21 at 16:05
@MutahirKiani I've made an edit to my post, this should let you replace the characters programmatically. – lejlun Aug 03 '21 at 16:19
Thanks man this solved my problem. Have a nice day :) – Mutahir Kiani Aug 03 '21 at 16:49
@MutahirKiani No problem , If it worked make sure to mark the solution as accepted. – lejlun Aug 03 '21 at 16:56
I am sorry I cant make it because I have only 13 reputations. People with more than 15 reputations can vote. – Mutahir Kiani Aug 04 '21 at 08:37

score 1 · Answer 3 · answered Aug 03 '21 at 16:01

1

\ is used to escape characters. Add an extra \ to get past it:

var path = "S:\\C\\2020\\ABCDEF"
    alert(path)

answered Aug 03 '21 at 16:01

Tushar Shahi

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I am getting this variable from spring boot controller and I have no control over this variable. I cant directly change it. – Mutahir Kiani Aug 03 '21 at 16:03
Change it in your front end right? Make a copy and add extra `\`. Is that not possible? – Tushar Shahi Aug 03 '21 at 16:04
is there any way to use replace function and replace single backslash with double backslash? – Mutahir Kiani Aug 03 '21 at 16:05

Javascript single backslash in string variable not working

3 Answers3