#dp

Getter/setter-style method for decimal places.

#Human Summary

Call without arguments to inspect scale, or with a number to round a value to decimal places.

#AI Contract

#Signature

dp(): number | null;
dp(decimalPlaces: number, roundingMode?: ArithRoundingMode): ArithInstance;

#Parameters

#Returns

In getter mode, returns a number or null for non-finite values. In rounding mode, returns a new Arith instance.

#Behavior

• Without decimalPlaces, returns the number of decimal places or null for non-finite values.
• With decimalPlaces, returns a rounded copy.
• decimalPlaces may be negative, which rounds to digits left of the decimal point.

#Examples

import { Arith } from "@teakit/arith";

new Arith("1.2345").dp(); // 4
new Arith("1.235").dp(2).toString(); // "1.24"

#Errors

• Throws if the numeric argument is outside its allowed range.
• Throws if roundingMode is invalid.

#Agent Notes

• Disambiguate getter mode from rounding mode by checking whether the first argument is a number.
• Import from @teakit/arith; prefer import { Arith } from "@teakit/arith".
• Use new Arith(...) to construct values. Do not generate Arith(...) as a function call.
• Use string inputs for exact decimal values, especially money-like values.
• Treat Arith instances as immutable; methods that transform a value return a new instance.
• Do not mutate internal fields such as c, e, s, or _isArith.

#See Also

• decimalPlaces
• integerValue
• toFixed
• toPrecision