javascript - How do I Programmatically create a double escape?

Question

I have a string with an escape character:

var a = "Hello World";

I want to split the string into an array of characters which includes the escape character:

var a = "Hello World";
/* Do something here */
a; // I want output: ["H","e","l","l","o",""," ","W","o","r","l","d"]

Typically I split the string using:

a=a.split('');

But of course this does not work because the escape character is ignored during the split.

var a = "Hello World";
a=a.split('');
a; // outputs ["H","e","l","l","o"," ","W","o","r","l","d"]

Now I know in order to get the results I want I have to use a double escape. I know that my string should look like:

var a = "Hello\ World";

But that is not the string I have, I am not typing in the string manually it is generated. So I fully understand that I need a double escape but I can not manually create one. I need to know how to programmatically transform "Hello World" into "Hello\ World".

Is there some magical function that will escape all backslashes? Is there a doubleEscape() function I am not aware of, or maybe there is some regex replace function that can help me out.

I do not want the answer "use a double escape" or "your string needs to be 'Hello World'. I am fully aware that this is what I need to do but I need to programmatically escape the escape character, it can not be done manually.

I have attempted something like this:

var a = "Hello World";
a = a.replace("", "");

But of course this doesn't work because the escape character is ignored during the replace. I have tried things like:

var a = "Hello World";
a = a.replace("", "");

But this gives an error. I believe it is interpreting the search parameter as a regex, which is an invalid regex, which causes an error.

Another post that was similar suggested this:

var a = "Hello World";
a = a.replace(/\/g, '\\');
a; // outputs "Hello World";

This does not work. The string remains as if the replace was not executed.

Any suggestions?

Answer 1

No, you can't. It's not that the backslash is ignored in the split.

Instead, the problem is that the backslash isn't in the string:

"Hello World"; // "Hello World"

Therefore, once the string literal has been parsed, you can't recover the slash.

However, ECMAScript 6 introduces template strings. And with String.raw, you can recover the raw string form:

`Hello World`;           //  "Hello World"
String.raw`Hello World`; //  "Hello World"