javascript - Why does console.log(true, 't') print true ""? - Stack Overflow

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In Chrome, the following

console.log(true, '\t');

will print

true "  "

Why are there quotes hanging around?

(Notice that console.log(true + '', '\t') will only print true, in the same way that console.log('a', '\t'); will only print a.)

In Chrome, the following

console.log(true, '\t');

will print

true "  "

Why are there quotes hanging around?

(Notice that console.log(true + '', '\t') will only print true, in the same way that console.log('a', '\t'); will only print a.)

• javascript
• google-chrome

Share Improve this question Follow edited Aug 27, 2012 at 18:08 Randomblue asked Aug 27, 2012 at 18:02 RandomblueRandomblue 116k150150 gold badges362362 silver badges557557 bronze badges 13

• Not 100% sure, but my guess is because \t is a string expression representing a tab, chrome shows " " so you can distinguish that it is actually working. – Robert H Commented Aug 27, 2012 at 18:05
• @asawyer: Doesn't happen for console.log('a', '\t') ! – Randomblue Commented Aug 27, 2012 at 18:05
• 3 Note: It doesn't matter if you have "\t" or "". As lobg as it is a string it will print it with quotes after the primitive value true. – some Commented Aug 27, 2012 at 18:10
• 1 i tried console.log(true,'a\t') it prints true "a ", but console.log('a\t',true) prints a true(it has something to do with a previous boolean i think – Ankur Commented Aug 27, 2012 at 18:10
• 1 You keep editing the question. With true + "" you convert it to a sting, so console.log(true + '', '\t') is the same as console.log(string,string). You can test the type if you do typeof (true + ''). – some Commented Aug 27, 2012 at 18:18

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2 Answers 2

Sorted by: Reset to default 10

Basically there are two overloads to console.log:

console.log(formatString, args) and console.log(arg1, arg2, ...).

More specifically, per the source code, if the first parameter is a string then it treats it as a format string for the other parameters. Otherwise, each parameter is output directly.

Thus console.log(true + '', '\t') outputs 'true' because the first parameter is a string and there is no placeholder for the \t, and console.log(true, '\t') will output both parameters because true is not a string.

I decided to play around with it

console.log(true, '\t');
true "  "

and then I tried the opposite

console.log(false, '\t');
false " " 

Not sure why but false gives back only one space, while true gives back two o_O... Also if \t is in the beginning there is no issue

console.log('\t', true);
     true

It also doesn't matter what happens after it but it seems that the first parameter if its a boolean in general, will influence all the escaped tabs after with quotes.

console.log(false, '\t', '\t');
false " " " "

So it definitely has something to do with the first paramater being a boolean because if you try it with strings, it behaves pletely normally. I guess its a quirky thing with Google Chrome? I'll need to find the source code to actually see it.

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