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Javascript number formatter (Java DecimalFormat Implemented in Javascript)
/**
* @class DecimalFormat
* @constructor
* @param {String} formatStr
* @author Oskan Savli
*/
function DecimalFormat(formatStr)
{
/**
* @fieldOf DecimalFormat
* @type String
*/
this.prefix = '';
/**
* @fieldOf DecimalFormat
* @type String
*/
this.suffix = '';
/**
* @description Grouping size
* @fieldOf DecimalFormat
* @type String
*/
this.comma = 0;
/**
* @description Minimum integer digits to be displayed
* @fieldOf DecimalFormat
* @type Number
*/
this.minInt = 1;
/**
* @description Minimum fractional digits to be displayed
* @fieldOf DecimalFormat
* @type String
*/
this.minFrac = 0;
/**
* @description Maximum fractional digits to be displayed
* @fieldOf DecimalFormat
* @type String
*/
this.maxFrac = 0;
// get prefix
for (var i=0; i<formatStr.length; i++) {
if (formatStr.charAt(i) == '#' || formatStr.charAt(i) == '0') {
this.prefix = formatStr.substring(0,i);
formatStr = formatStr.substring(i);
break;
}
}
// get suffix
this.suffix = formatStr.replace(/[#]|[0]|[,]|[.]/g , '');
// get number as string
var numberStr = formatStr.replace(/[^0#,.]/g , '');
var intStr = '';
var fracStr = '';
var point = numberStr.indexOf('.');
if (point != -1) {
intStr = numberStr.substring(0,point);
fracStr = numberStr.substring(point+1);
}
else {
intStr = numberStr;
}
var commaPos = intStr.lastIndexOf(',');
if (commaPos != -1) {
this.comma = intStr.length - 1 - commaPos;
}
intStr = intStr.replace(/[,]/g , ''); // remove commas
fracStr = fracStr.replace(/[,]|[.]+/g , '');
this.maxFrac = fracStr.length;
var tmp = intStr.replace(/[^0]/g , ''); // remove all except zero
if (tmp.length > this.minInt)
this.minInt = tmp.length;
tmp = fracStr.replace(/[^0]/g , '');
this.minFrac = tmp.length;
}
/**
* @description Formats given value
* @methodOf DecimalFormat
* @param {String} numberStr
* @return {String} Formatted number
* @author Oskan Savli
*/
DecimalFormat.prototype.format = function(numStr) { // 1223.06 --> $1,223.06
// remove prefix, suffix and commas
var numberStr = this.formatBack(numStr).toLowerCase();
// do not format if not a number
if (isNaN(numberStr) || numberStr.length == 0)
return numStr;
//scientific numbers
if (i = numberStr.indexOf("e") != -1) {
var n = Number(numberStr);
if (n=="Infinity" || n=="-Infinity") return numberStr;
numberStr = n+"";
if(numberStr.indexOf('e') != -1) return numberStr;
}
var negative = false;
// remove sign
if (numberStr.charAt(0) == '-') {
negative = true;
numberStr = numberStr.substring(1);
}
else if (numberStr.charAt(0) == '+') {
numberStr = numberStr.substring(1);
}
var point = numberStr.indexOf('.'); // position of point character
var intStr = '';
var fracStr = '';
if (point != -1) {
intStr = numberStr.substring(0,point);
fracStr = numberStr.substring(point+1);
}
else {
intStr = numberStr;
}
fracStr = fracStr.replace(/[.]/ , ''); // remove other point characters
var isPercentage = this.suffix && this.suffix.charAt(0) === '%';
// if percentage, number will be multiplied by 100.
var minInt = this.minInt, minFrac = this.minFrac, maxFrac = this.maxFrac;
if (isPercentage) {
minInt -= 2;
minFrac += 2;
maxFrac += 2;
}
if (fracStr.length > maxFrac) { // round
//case 6143
var num = new Number('0.' + fracStr);
num = (maxFrac == 0)? Math.round(num) : num.toFixed(maxFrac);
// toFixed method has bugs on IE (0.7 --> 0)
fracStr = num.toString(10).substr(2);
var c = (num>=1)? 1:0; //carry
var x, i=intStr.length-1;
while (c) { //increment intStr
if (i==-1) {
intStr = '1'+intStr;
break;
}
else {
x = intStr.charAt(i);
if (x==9) {x='0'; c=1;}
else {x = (++x)+''; c=0;}
intStr = intStr.substring(0,i) + x + intStr.substring(i+1,intStr.length);
i--;
}
}
}
for (var i=fracStr.length; i<minFrac; i++) { // if minFrac=4 then 1.12 --> 1.1200
fracStr = fracStr + '0';
}
while (fracStr.length > minFrac && fracStr.charAt(fracStr.length-1) == '0') { // if minInt=4 then 00034 --> 0034)
fracStr = fracStr.substring(0,fracStr.length-1);
}
for (var i=intStr.length; i<minInt; i++) { // if minInt=4 then 034 --> 0034
intStr = '0' + intStr;
}
while (intStr.length > minInt && intStr.charAt(0) == '0') { // if minInt=4 then 00034 --> 0034)
intStr = intStr.substring(1);
}
if (isPercentage) { // multiply by 100
intStr += fracStr.substring(0,2);
fracStr = fracStr.substring(2);
}
var j = 0;
for(var i=intStr.length; i>0; i--) { // add commas
if (j != 0 && j%this.comma == 0) {
intStr = intStr.substring(0,i) + ',' + intStr.substring(i);
j = 0;
}
j++;
}
var formattedValue;
if (fracStr.length > 0)
formattedValue = this.prefix + intStr + '.' + fracStr + this.suffix;
else
formattedValue = this.prefix + intStr + this.suffix;
if (negative) {
formattedValue = '-' + formattedValue;
}
return formattedValue;
}
/**
* @description Converts formatted value back to non-formatted value
* @methodOf DecimalFormat
* @param {String} fNumberStr Formatted number
* @return {String} Original number
* @author Oskan Savli
*/
DecimalFormat.prototype.formatBack = function(fNumStr) { // $1,223.06 --> 1223.06
fNumStr += ''; //ensure it is string
if (!fNumStr) return ''; //do not return undefined or null
if (!isNaN(fNumStr)) return this.getNumericString(fNumStr);
var fNumberStr = fNumStr;
var negative = false;
if (fNumStr.charAt(0) == '-') {
fNumberStr = fNumberStr.substr(1);
negative = true;
}
var pIndex = fNumberStr.indexOf(this.prefix);
var sIndex = (this.suffix == '')? fNumberStr.length : fNumberStr.indexOf(this.suffix, this.prefix.length+1);
if (pIndex == 0 && sIndex > 0) {
// remove suffix
fNumberStr = fNumberStr.substr(0,sIndex);
// remove prefix
fNumberStr = fNumberStr.substr(this.prefix.length);
// remove commas
fNumberStr = fNumberStr.replace(/,/g , '');
if (negative)
fNumberStr = '-' + fNumberStr;
if (!isNaN(fNumberStr))
return this.getNumericString(fNumberStr);
}
return fNumStr;
}
/**
* @description We shouldn't return strings like 1.000 in formatBack method.
* However, using only Number(str) is not enough, because it omits . in big numbers
* like 23423423423342234.34 => 23423423423342236 . There's a conflict in cases
* 6143 and 6541.
* @methodOf DecimalFormat
* @param {String} str Numberic string
* @return {String} Corrected numeric string
* @author Serdar Bicer
*/
DecimalFormat.prototype.getNumericString = function(str){
//first convert to number
var num = new Number(str);
//check if there is a missing dot
var numStr = num + '';
if (str.indexOf('.')>-1 && numStr.indexOf('.')<0){
//check if original string has all zeros after dot or not
for (var i=str.indexOf('.')+1;i<str.length;i++){
//if not, this means we lost precision
if (str.charAt(i) !== '0') return str;
}
return numStr;
}
return str;
}
The MIT License (MIT)
Copyright (c) 2014, Gerger (www.gerger.co)
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
@tburch

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tburch commented Feb 18, 2011

There is a bug when you try to format 0. DecimalFormat.prototype.formatBack needs to check if fNumStr !== 0. See https://gist.github.com/832247/ab5a8057c6ce8e3977e87d55cf48585ba8a65878

@oskansavli

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Owner

oskansavli commented Feb 21, 2011

Fixed now, thanks.

@hennito

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hennito commented Mar 28, 2012

Is this code usable under any open source license (MIT, EPL, APACHE) ?

@pixelzoom

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pixelzoom commented Sep 4, 2013

I'm also interested in the licensing.

@abhimanyumshetti

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abhimanyumshetti commented May 9, 2014

When I try in to format

0.0e0 

with the number '1' it should output

1.0e0 

but it formats it as

1.00e

Is this a know issue?

@dottertrotter

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dottertrotter commented May 21, 2014

Has a license been applied to this yet? Thanks.

@jjromannet

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jjromannet commented Dec 18, 2014

For new DecimalFormat('#.00%').format(.01);
it returns: 01%
I fixed this problem in: https://gist.github.com/jjromannet/617f547e15d3d8a840d1

What has been mentioned before by abhimanyumshetti, output is actually consistent with Java object

@mantoshelis

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mantoshelis commented Aug 25, 2017

For 0.000000000000000001 it formats: 1e18

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