Simple variable check returns false, should be true

Question

A little background.

I am receiving a message from my server that comes in the form of <Buffer 00 00 00> I using the Node string_decoder function to turn this into a utf8 encoded string:

var StringDecoder = require('string_decoder').StringDecoder;
var decoder = new StringDecoder('utf8');

global.message = null;

 client.on('data', function(chunk) {
   console.log(`New Message ${decoder.write(chunk)}`);
   message = decoder.write(chunk);
 })

When running, this logs out New Message OK which is correct

In another function, I am then looping until the global variable is equal to OK, however I am running into some problems:

console.log(`Global vari ${message}`);
if(message != "OK"){
    setTimeout(check, 1000);
} else {
    return cb(true);
}

The above logs out Global vari OK however the if statement fails. I have done a typeof check on message, and it outputs string as expected.

I'm stumped as to what is going on here, but I cannot figure it out for the life of me.

Console statements are tricky and may not be outputting in the order of your code. Try logging in the `else` statement. — chazsolo, Feb 02 '17 at 12:23
maybe try this to make sure everything matches .tostring().toupper().trim() — krisph, Feb 02 '17 at 12:24

score 1 · Answer 1 · answered Feb 02 '17 at 12:24

1

Try to trim before comparaison to make sure there no extra spaces :

if(sanitized.trim() != "OK"){
    setTimeout(check, 1000);
} else {
    return cb(true);
}

Hope this helps.

answered Feb 02 '17 at 12:24

Zakaria Acharki

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score 0 · Answer 2 · edited May 23 '17 at 10:29

Are you sure it doesn't contain any BOM character or any other invisible data that makes it not equal to OK?

You can try removing everything but the letters, like:

let sanitized = message.replace(/\W/g, '');
console.log(`Global vari ${sanitized}`);
if(sanitized != "OK"){
    setTimeout(check, 1000);
} else {
    return cb(true);
}

and see what it prints now.

You can see these answers about BOM characters and the problems they cause:

Simple variable check returns false, should be true

2 Answers2