Question

I’d like to write a function that works reliably to get the string literal from a JavaScript string—we can call it f.

For example:

f('hello world') //-> 'hello world' (or "hello world")
f('hello "world"') //-> 'hello "world" (or "hello \"world\"")
f("hello 'world'") //-> "hello 'world'"
f("hello \"'world'\"") //-> "hello \\\"'world'\\\""
f("hello \n world") //-> "hello \\n world"

And so for any string str

str = eval(f(str))

I don’t care about the single quotes thing too much.

I currently am just doing:

var f = function(str) {
  return '"' + str.replace(/"/g, '\"') + '"';
}

but that obviously doesn’t cover everything.

---

This is for a documentation system.

Answer 1

If I’ve read what your after correctly, how about;

var Map = {
    10: "n",
    13: "r",
    9:  "t",
    39: "'",
    34: '"',
    92: "\\"
};
function f(str) {
    var str = '"' + str.replace(/[\n\r\t\"\\]/g, function(m) {
        return "\\" + Map[m.charCodeAt(0)]
    }) + '"';
    print(str);
}

f('hello world') //-> 'hello world' (or "hello world")
f('hello "world"') //-> 'hello "world" (or "hello \"world\"")
f("hello 'world'") //-> "hello 'world'"
f("hello \"'world'\"") //-> "hello \\\"'world'\\\""
f("hello \n world") //-> "hello \\n world"

>>"hello world"
>>"hello \"world\""
>>"hello 'world'"
>>"hello \"'world'\""
>>"hello \n world"