CODEWITHSUNDEEP
javascriptunicodeascii
agweber
agweber

Reputation: 1275

I think JS is giving me Unicode when all I want is ASCII

I'm trying to take a character and increment or decrement it. I'm attempting to use String.fromCharCode to accomplish this. While the following works in a console

'Na' + String.fromCharCode(78 + n) // n is 2 in this example, can even hard-code it

seems to work properly and gives me NaP, something else in my code is giving me Na̎ instead.

Here's the code block that is being executed

if (ifTypes(a, b, 'integer', 'NaN')) { // disregard this, inside code IS executing
    console.log("a: " + JSON.stringify(a) + "   b: " + JSON.stringify(b));
    var n = a[1] === 'NaN' ? b[0] : a[0];
    var output = 'Na' + String.fromCharCode(78 + n);
    console.log("output: " + output);
    return output;
}

From the console for verification:

a: [null,"NaN"]   b: ["2","integer"]
output: Na̎ // <-- SO's code highlighter is messing that up

And yes, if anyone recognizes what I'm doing, I am implementing the interpreter from xkcd's 1537. If you want to see this code in action and maybe try to read through my console output, I've got it online here. Just click in the lighter bar and press enter, it's just simulating a terminal.

I suspect the problem is some strange ascii/unicode toggle. I've tried putting the 'Na' inside the String.fromCharCode but it gives the similar results. Though a should be [NaN, "NaN"], I don't think that's the issue. I do need to track down that bug too.

Upvotes: 0

Views: 55

Answers (2)

kdbanman
kdbanman

Reputation: 10557

n is a string, not an integer, so the addition isn't doing what you expect.

Change

var output = 'Na' + String.fromCharCode(78 + n);

to 

var output = 'Na' + String.fromCharCode(78 + parseInt(n));

Upvotes: 1

sainaen
sainaen

Reputation: 1578

I think the problem is that you're adding "2" and 78, instead of 2 and 78.

function print(s) {
  document.querySelector("#result").innerHTML += "<pre>" + s + "</pre>";
}

var a = [null, "NaN"];
var b = ["2", "integer"];

var n = a[1] === 'NaN' ? b[0] : a[0];
var output = 'Na' + String.fromCharCode(78 + n);
print("output 1: " + output);

output = 'Na' + String.fromCharCode(78 + (typeof n == "number" ? n : parseInt(n, 10)));
print("output 2: " + output);
<div id="result"></div>

Upvotes: 2

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