I need to round a value with 2 decimal places that I receive from a web service. To do this i use this methods toFixed and parseFloat because I need the final value in a float.
However when I have this value "5.5000000" he shows me the value with only one decimal place "5.5"...
I did in that way:
var num = 5.5000000;
var n = num.toFixed(2);
var numFinal = parseFloat(n);
You have to call toFixed after parseFloat:
parseFloat(yourString).toFixed(2)
You can do something like this
/**
* Convert the value to the Number with the precision.
* #param {Number} value value to be converted
* #param {Number} [precision=0] number of decimal places
* #returns {Number} converted number.
*/
function toNumber (value, precision) {
precision = precision || 0;
if (precision === 0) {
return value * 1;
} else {
return Number((value * 1).toFixed(precision));
}
}
Short Answer: There is no way in JS to have Number datatype value with trailing zeros after a decimal.
Long Answer: Its the property of toFixed or toPrecision function of JavaScript, to return the String. The reason for this is that the Number datatype cannot have value like a = 2.00, it will always remove the trailing zeros after the decimal, This is the inbuilt property of Number Datatype. So to achieve the above in JS we have 2 options
Either use data as a string or
Agree to have truncated value with case '0' at the end ex 2.50 -> 2.5. Number Cannot have trailing zeros after decimal
Related
I want my function to be typed in 2 scenarios depending on how the user uses the function. If the user uses just a number they type of param will be number. if they use an object for options it will be of type { num: number; dp: number }. This I have working but I want it to be typed for intellisense so when the user hovers they can see type num represents the input number and type dp represents the number of digits to round to but if they just type a number as param then that to be typed as 'a number to round to the nearest int' This is the code I have but cannot get it to do exactly what I want. Any help would be appreciated! Thank you.
/**
* Returns a rounded numbers. If dp isn't entered the number returned will be rounded to the nearest integer.
* #param param - The rounding options or a number to round to an int.
* #param dp - The decimal places to round to.
* #param num - The number to round.
* #returns An rounded number.
*/
const round = (param: { num: number; dp: number } | number) => {
if (typeof param === 'number') return Math.round(param);
const { dp, num } = param;
return Math.round(num * Math.pow(10, dp)) / Math.pow(10, dp);
};
Simply the problem is how to detect both scenarios in TS/JSDoc and type for it
function truncDigits(inputNumber, digits) {
const fact = 10 ** digits;
return Math.trunc(inputNumber * fact) / fact;
}
truncDigits(27624.399999999998,2) //27624.4 but I want 27624.39
I need to truncate a float value but don't wanna round it off. For example
27624.399999999998 // 27624.39 expected result
Also Math.trunc gives the integer part right but when you Math.trunc value 2762439.99 it does not give the integer part but gives the round off value i.e 2762434
Probably a naive way to do it:
function truncDigits(inputNumber, digits) {
return +inputNumber.toString().split('.').map((v,i) => i ? v.slice(0, digits) : v).join('.');
}
console.log(truncDigits(27624.399999999998,2))
At least it does what you asked though
Try this:
function truncDigits(inputNumber, digits){
return parseFloat((inputNumber).toFixed(digits));
}
truncDigits(27624.399999999998,2)
Your inputs are number (if you are using typescript). The method toFixed(n) truncates your number in a maximum of n digits after the decimal point and returns it as a string. Then you convert this with parseFloat and you have your number.
You can try to convert to a string and then use a RegExp to extract the required decimals
function truncDigits(inputNumber: number, digits: number) {
const match = inputNumber.toString().match(new RegExp(`^\\d+\\.[\\d]{0,${digits}}`))
if (!match) {
return inputNumber
}
return parseFloat(match[0])
}
Note: I'm using the string version of the RegExp ctor as the literal one doesn't allow for dynamic params.
Input Number : 3266.528
deciaml Point: 1
output for decimal point (1) : 3266.5
output for decimal point (2) : 3266.53
output for decimal point (3) : 3266.528
output for decimal point (4) : 3266.5280
How to round numbers based on decimal point given as above. Based on input number and decimal point, I would like to get the number rounded as above
use .toFixed() on the number. The parameter you give will determine the number of digits to return after the decimal point.
let num = 3266.5390
console.log(num.toFixed(2)) // answer will be 3266.54
console.log(num.toFixed(3)) // answer will be 3266.539
A popular way in javascript is simply the following :
const num = 3266.528;
const result = Math.round(num * 100) / 100;
where the 100 will round to 2 decimal places, 1000 for 3 places, etc.. You can parameterize and make use of Math.pow(10, idx) if you'd like e.g.
const round = (n, dec) => (Math.round(n * Math.pow(10, dec)) / Math.pow(10, dec));
Good day Everyone!
I want to know how to return the output with two decimal places. Instead of 10,000 I want it to return 10,000.00. Also I already put .toFixed(2) but it's not working.
When the amount has decimal number other than zero, the values appear on the printout, but when the decimal number has a zero value, the Zeros won't appear on the printout.
Also, I have added a value of Wtax that was pulled-out on a "Bill Credit" Transaction.
Output:
Numeral.js - is a library that you can use for number formatting.
With that you can format your number as follows:
numeral(10000).format('$0,0.00');
Hope this will help you.
You can try this
var x = 1000; // Raw input
x.toFixed(2).replace(/(\d)(?=(\d{3})+\.)/g, '$1,') //returns you 1,000.00
Alternately you can use Netsuite's currency function too
nlapiFormatCurrency('1000'); // returns you 1,000.00
nlapiFormatCurrency('1000.98'); // returns you 1,000.98
You might consider below code. It can round off decimal values based on the decimal places.
This also addresses the issue when rounding off negative values by getting first the absolute value before rounding it off. Without doing that, you will have the following results which the 2nd sample is incorrect.
function roundDecimal(decimalNumber, decimalPlace)
{
//this is to make sure the rounding off is correct even if the decimal is equal to -0.995
var bIsNegative = false;
if (decimalNumber < 0)
{
decimalNumber = Math.abs(decimalNumber);
bIsNegative = true;
}
var fReturn = 0.00;
(decimalPlace == null || decimalPlace == '') ? 0 : decimalPlace;
var multiplierDivisor = Math.pow(10, decimalPlace);
fReturn = Math.round((parseFloat(decimalNumber) * multiplierDivisor).toFixed(decimalPlace)) / multiplierDivisor;
fReturn = (bIsNegative) ? (fReturn * -1) : fReturn;
fReturn = fReturn.toFixed(decimalPlace)
return fReturn;
}
Below are the test sample
And this test sample after addressing the issue for negative values.
View this code:
function testprecision(){
var isNotNumber = parseFloat('1.3').toPrecision(6);
alert(typeof isNotNumber); //=> string
}
I would have expected a number. If 'isNotNumber' should be a real number, recasting is the solution:
alert(typeof parseFloat(isNotNumber)) //=> number
[Edit]
thanks for your answers. Precision is not so precise a term I conclude. It can represent the total number of digits of a number, or the number of fractional digits. Most people in the Netherlands (where I come from) think of precision in the 'number of fractional digits'-way. The javascript toPrecision method concerns the first representation, so this is confusing. Anyway, the method makes it possible to introduce 'false precision', am I right? For the second meaning we have toFixed, the same goes for that (returns string, possibility of false precision).
Anyway, having made reinventing the wheel my main hobby, I played around to construct a javascript float object, using the knowledge I gathered here. Maybe it's usefull for someone out there, or maybe one of you have better ideas?
function Float(f,nDec) {
var Base = this,val;
setPrecision( nDec || 2 );
set( f || 0, nDec || Base.precision );
Base.set = set;
Base.ndec = setPrecision;
/** public setprecision
* sets a value for the number of fractional
* digits (decimals) you would like getf to
* return. NB: can't be more than 20.
* Returns the Float object, so allows method
* chaining
* #param {Number} iPrecision
*/
function setPrecision(iPrecision) {
var ix = parseInt(iPrecision,10) || 2;
Base.precision = ix >= 21 ? 20 : ix;
return Base;
}
/** public set
* sets the 'internal' value of the object. Returns
* the Float object, so allows method chaining
* #param {Number} f
* #param {Number} ndec
*/
function set(f,ndec) {
val = parseFloat(f) || 0;
if (ndec) { setPrecision(ndec); }
Base.val = val;
return Base;
}
/** public get:
* return number value (as a float)
*/
Base.get = function(){
var ndec = Math.pow(10,Base.precision),
ival = parseInt(val*ndec,10)/ndec;
Base.val = ival;
return Base.val;
};
/** public getf
* returns formatted string with precision
* (see Base.setPrecision)
* if [hx] is supplied, it returns
* the float as hexadecimal, otherwise
* #param {Boolean} hx
*/
Base.getf = function(hx){
var v = Base.val.toFixed(Base.precision);
return hx ? v.toString(16) : v;
};
/** public add
* adds [f] to the current value (if [f] is a
* Float, otherwise returns current value)
* optionally sets a new number of decimals
* from parameter [ndec]
* #param {Number} f
* #param {Number} ndec
*/
Base.add = function(f,ndec){
if ( parseFloat(f) || val===0) {
set(Base.val+parseFloat(f));
if (ndec) { setPrecision(ndec);}
}
return Base.get();
};
/** toString
* returns the internal value of the Float object
* functions like a getter (supposedly)
*/
Base.toString = Base.get;
}
usage/example:
var xf = new Float(); //=> value now 0.0
xf.set(0.86/0.8765,17).add(3.459);
alert(xf+'|'+xf.getf()); //=> 4.440175128351398|4.44017512835139800
From the docs: "Returns a string representing the Number object to the specified precision."
toPrecision() seems intended for formatting output, in which case a string is the most reasonable outcome. It represents the final output in a form that will not be mangled by further manipulation.
If you are looking to do some truncation of precision for calculation reasons, I tend to multiply by 10^n where n is the digits I want to keep, take an integer from that and then divide again by the same. This isn't perfect though: in some situations you may invite an overflow. Frankly, I prefer to do more complex financial calculations on the server, where I have a currency, binary coded decimal or similar numeric types.
Assume you have a number like '1.6'. If you format it to have 6 zeroes to the right, you would get a '1.600000'. To the computer, it is still the same number as 1.6, but to you and your website, it is not the same if all your numbers are of different lenghts (which could hurt a parser, for instance).
So, as to avoid it, toPrecision returns a string, or else the interpreter would reformat the number to become '1.6' again.
The purpose of toPrecision is to truncate the significant decimal digits of a Number to a specified amount. But the datatype of the internal representations of Numbers is binary IEEE-754 double. Therefore it's impossible to store the precise return value in a Number most of the times. As a result of this impreciseness, the return value would have an infinite amount of decimal digits which would render toPrecision void.
So the only reasonable solution to this problem is to return decimal digits. And currently the only reasonable JS datatype for decimal digits is a String.
Here's an example to clarify the impreciseness of Numbers if used for decimal digits:
// the following looks like something with 2 decimal digits:
var number = 1.6;
// but in fact it's a number with an infinite amount of decimal digits.
// let's look at the first 30 of them:
alert(number.toPrecision(30));
// 1.60000000000000008881784197001
Because it is a formatting function.
You need a string for trailing zeros. Currency display is a good example.
The problem is the use of toPrecision. Try it without.
var isNotNumber = parseFloat('1.3');
alert(typeof isNotNumber); //=> number