[REQUEST] Unit symbol for normal units

[nissaba]

I was using MASS and when I tryed to get MASS.pounds.symbol it gave me a warnign that the property did not exist.
I fixed it by vreating an extension, possilby youi can re-use it in the project.

extension on MASS {
String get symbol => _symbol();
String _symbol() {
switch (this) {
case MASS.kilograms:
return 'kg';
case MASS.grams:
return 'k';
case MASS.ettograms:
return 'hg';
case MASS.pounds:
return 'lbs';
case MASS.ounces:
return 'oz';
case MASS.quintals:
return 'q';
case MASS.tons:
return 't';
case MASS.milligrams:
return 'mg';
case MASS.femtograms:
return 'fg';
case MASS.picograms:
return 'pg';
case MASS.nanograms:
return 'ng';
case MASS.micrograms:
return 'μg';
case MASS.decigrams:
return 'dg';
case MASS.uma:
return 'u';
case MASS.carats:
return 'ct';
case MASS.centigrams:
return 'cg';
case MASS.pennyweights:
return 'dwt';
case MASS.troyOunces:
return 'ozt';
case MASS.stones:
return 'st';
}
}
}

[nissaba]

I see it is missing for all supported unit types. it would be very usefull to have this in the package.