CODEWITHSUNDEEP
javascriptnumbers
Lukas Oppermann
Lukas Oppermann

Reputation: 2938

JavaScript Number preserve leading 0

I have a problem, I build a very simple javascript search for postal codes. I am using JS Numbers because I want to check if the passed number (search term) is less||equal or more||equal to the max and min.

value >= splitZips[0] && value <= splitZips[1]

But the Javascript Number var type deletes leading 0, which is a problem because I have postal codes like 01075 and also postal codes like 8430. So it can not find the small 4 digit codes.

Any idea how to fix this?

Upvotes: 3

Views: 7047

Answers (3)

alex
alex

Reputation: 490153

Represent them as a String. Outside of strict mode, a leading zero denotes an octal number otherwise.

Also, why would a leading zero have any significance when calculating numbers? Just use parseInt(num, 10) if you need to.

Upvotes: 7

abuduba
abuduba

Reputation: 5042

Instead a parseInt you could use type casting :)

"0123">"122" // false
+"0123">"122" // true  | that  means: 123>"122"

Btw, what more you can use a each of bitwise operators :

 ~~"0123"   
 "0123"|0  
 "0123"&"0123" 
 "0123">>0
 "0123"<<0

With the same effect :)

Upvotes: 1

nnnnnn
nnnnnn

Reputation: 150010

Store and display the postcodes as strings, thus retaining the leading zeros. If you need to make a numerical comparison convert to number at the time. The easiest way to convert is with the unary plus operator:

var strPC = "01745",
    numPC = +strPC;

alert(numPC === +"01745"); // true

+value >= +splitZips[0] && +value <= +splitZips[1];
// etc.

Before you start comparing you might want to ensure the entered value actually is numeric - an easy way to be sure it is a four or five digit code with or without leading zeros is with a regex:

/^\d{4,5}$/.test(searchTerm)       // returns true or false

Upvotes: 2

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