[Feature Request] Currency Pipe: improved digit info options

Which @angular/* package(s) are relevant/related to the feature request?

common

Description

A common way to display currencies (at least in US) is to omit the cents if the price is a round number, or to show two digits if the price is not a round number. For example, for 3 dollars, $3, and for 3.1 dollar, $3.10.

There is no way to accomplish this with the current currency pipe, which only takes a range for the number of digits after the decimal. The only options either make the first price $3.00 and the second $3.10, or the first price $3 and the second $3.1.

Proposed solution

Extend the digitsInfo format. Currently, the format is {minIntegerDigits}.{minFractionDigits}-{maxFractionDigits}. As an alternative, we could offer {minIntegerDigits}.{allowedFractionDigits1},{allowedFractionDigits2}[,...]. So the digitsInfo for the format above would be 1.0,2.

Alternatives considered

Alternately, one could use an *ngIf to change out the element with the currency, and use two elements, each with a currency pipe to accomplish the above. Obviously, that is kind of messy.

[kbrilla]

I think one soultion would be to create new Pipes based on Intl API

const format = new Intl.NumberFormat("en-US", {style: 'currency', minimumFractionDigits: 2, trailingZeroDisplay: 'stripIfInteger', currency: 'USD'}); 

format.format(3)    
//  $3
format.format(3.1)
//  $3.10

If not maybe reusing the term trailingZeroDisplay option would be good for the current API with two values as in Intl API - NumberFormat NumberFormat

trailingZeroDisplay Experimental
A string expressing the strategy for displaying trailing zeros on whole numbers. The default is "auto".

"auto": keep trailing zeros according to minimumFractionDigits and minimumSignificantDigits.
"stripIfInteger": remove the fraction digits if they are all zero. This is the same as auto if any of the fraction digits is non-zero.

as for Intl API there are already polyfills for it here polyfill

[angular-robot[bot]]

Thank you for submitting your feature request! Looks like during the polling process it didn’t collect a sufficient number of votes to move to the next stage.

We want to keep Angular rich and ergonomic and at the same time be mindful about its scope and learning journey. If you think your request could live outside Angular’s scope, we’d encourage you to collaborate with the community on publishing it as an open source package.

You can find more details about the feature request process in our documentation.