Add ability to control number of fractional digits

[nmoinvaz]

This should resolve #57.

[nmoinvaz]

I can remove fixed option if you don't want it.

[sindresorhus]

What's the use-case for the fixed option?

[nmoinvaz]

There was no use case for fixed, I just added it as an alternative to precision for completeness. I will remove it.

[nmoinvaz]

It appears the proper way to do this is not through toFixed or toPrecision but through locale options when calling number.toLocaleString(locale, options). I can expose a localeOptions option which would allow users to set it through localeOptions: {minimumFractionDigits: 2, maximumFractionDigits: 2}, or I can keep with the digits options digits: 2 with a note that using digits will automatically format the number using the system default locale.

[nmoinvaz]

I have tried both ways, in two commits. I think the last commit is the best that has a localeOptions which is more configurable because both minimumFractionDigits and maximumFractionDigits can be set if desired.

[sindresorhus]

I agree with minimumFractionDigits and maximumFractionDigits, but they should be top-level options, not nested in localeOptions. And you need to document their default values.

[nmoinvaz]

The default values will be undefined because the when minimumFractionDigits and maximumFractionDigits is not set it will default to toPrecision(3) which has entirely different behavior.

[nmoinvaz]

Actually if you meant default value in the Object.assign for options, then I have included it.

[nmoinvaz]

Requested changes have been made again.

[sindresorhus]

It would be better to just do options = {}.

[nmoinvaz]

Then I would check Object.keys(options).length > 0 in the second if statement?

[sindresorhus]

Suggested change

	const numberString = toLocaleString(number, options.locale, localeOptions);
	const numberString = toLocaleString(number, options.locale, {
	...{
	options.minimumFractionDigits,
	options.maximumFractionDigits
	}
	});

[nmoinvaz]

localeOptions should be undefined if both minimumFractionDigits and maximumFractionDigits is not set - so that it does not get localized by toLocaleString.

[nmoinvaz]

Some of the requested changes have been made.