Fastest way to format an integer in JavaScript?

Question

There is a random number (not necessarily positive or integer), say, -14383040.327843. I want to turn it into "(14,383,040)". So to spell it:

negative number has to be in brackets
fraction part should be stripped off without rounding
every N decimal places (3 by default) from right to left there has to be a separator (, by default)
no leading zeros

What is the fastest (across major browsers) way to get such string?

@epascarello value < 0 ? '(' + String(value.toFixed(0)).split('').reverse().chunk(3).map(function(chunk) { return chunk.reverse().join(''); }).join(',') + ')' : String(value.toFixed(0)).split('').reverse().chunk(3).map(function(chunk) { return chunk.reverse().join(''); }).join(',') — Trident D'Gao
– Trident D'Gao, Commented Oct 23, 2014 at 19:10
Probably not fast, just tried it out "-231423421342134.327843".split(".")[0].replace(/\B(?=(\d{3})+(?!\d))/g, ",").replace(/^-(.+)/,"($1)"); — epascarello
– epascarello, Commented Oct 23, 2014 at 19:34

kennebec · Accepted Answer · 2014-10-23 19:03:39Z

1

(Math.round(-14383040.327843)).toLocaleString();


/*  returned value: (String)
-14,383,040
*/

This value is returned in IE8 and IE10, Firefox 33,Opera 25 and Chrome 38.

To replace the minus-hyphen with parens-

(Math.round(-14383040.327843)).toLocaleString().replace(/\-(.+)/,'($1)');

answered Oct 23, 2014 at 19:03

kennebec

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Comments

mainstreetmark · Accepted Answer · 2014-10-23 18:54:15Z

0

Try this.

x=-14383040.327843;
xf=Math.abs(x|0).toString().replace(/\B(?=(\d{3})+(?!\d))/g, ",");
xp=(x>0)?xf:"("+xf+")";

x is your variable, xf is formatted, and xp is for printing.

answered Oct 23, 2014 at 18:54

mainstreetmark

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