JSON.stringify () error in javascript

Question

I have the following code

var number = 0618260587

JSON.stringify(number)

the stringified result is 618260587 , the first zero is automatically truncated.

I tried the following fix

if(number.length<8)
        {
        var book1 = "0" + number;
        alert(book1);

but it alerts undefined. I am not sure

1) Why the stringified data truncates the first zero 2) I thought javascript adds two variables irrespective of type

Marc B · Accepted Answer · 2012-08-13 02:16:38Z

5

Leading zeroes are a display thing, and not normally part of numbers. There's an infinite number of invisible zeroes before/after every number, but they're not normally shown. If you want the leading zero, treat the number as a string:

var number = '0618260587';

As well, in most, numbers with a leading zero are treated as octal, not decimal. Bare leading zeroes can cause hard-to-track bugs because of this - it looks like a decimal to you, but it's some completely different number to the interpreters, eg..

0618260587 octal = 1616431 decimal

answered Aug 13, 2012 at 2:16

Marc B

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5 Comments

Thilo Over a year ago

+1 for the warning about octals. In his case (at least on Firefox), it actually works as a decimal, because he has the digit 8. If you changed 8 to 6, it will become octal. Is this fallback to decimal in the presence of invalid octal digits spec'd somewhere?

alex Over a year ago

Thank you for the explanation !! I would have done it , but I require the input to be a number and then stringify it . What is wrong with the fix I tried making?

Marc B Over a year ago

@alex: you're not using numberin your fix. book is undefined, making the whole result undefined.

alex Over a year ago

MarcB , apologies , I had changed the variable while putting the question up , I left that change , The problem still remains

Marc B Over a year ago

if number is still an int, then it has no .length. You have to convert it to a string first. That means your if() is failing, since a number can never have a length, so it's doing if (undefined < 8).

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