Cleanup some unit types (#88)

jscheiny · Nov 16, 2018 · eecac11 · eecac11
1 parent 3f6df97
commit eecac11
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Showing 2 changed files with 11 additions and 10 deletions.
diff --git a/src/measure/unitTypeArithmetic.ts b/src/measure/unitTypeArithmetic.ts
@@ -8,13 +8,13 @@ import {
     ProductOf,
 } from "../exponent";
 
-export type UnitWithSymbols<U extends Unit = Unit> = { [D in keyof U]+?: [string, NonNullable<U[D]>] };
-export type SymbolAndExponent = [string, Exponent];
-
 export interface Unit {
     [dimension: string]: Exponent | undefined;
 }
 
+export type UnitWithSymbols<U extends Unit = Unit> = { [D in keyof U]+?: [string, NonNullable<U[D]>] };
+export type SymbolAndExponent = [string, Exponent];
+
 // Multiplication
 
 /** Returns the product of two units. This is the sum of two dimension vectors. */
@@ -38,9 +38,9 @@ export type DivisorUnit<U extends Unit> = MultiplicandUnit<ExponentiateUnit<U, -
 // Exponentiation
 
 /** Returns the unit raised to a power. This is the scalar multiple of the dimension vector. */
-export type ExponentiateUnit<U extends Unit, N extends Exponent> = StripZeroes<
-    { [Dim in keyof U]: MultiplyExponents<GetExponent<U, Dim>, N> }
->;
+export type ExponentiateUnit<U extends Unit, N extends Exponent> = 0 extends N
+    ? {}
+    : 1 extends N ? U : { [Dim in keyof U]: MultiplyExponents<GetExponent<U, Dim>, N> };
 
 /** A type that is assignable from all units that can be raised to the N without producing an error. */
 export interface BaseUnit<N extends Exponent> {
@@ -62,8 +62,9 @@ export interface RadicandUnit<N extends Exponent> {
 // Utility types
 
 /** Removes all zero exponent dimensions from a dimension vector */
-type StripZeroes<U extends Unit> = Pick<U, NonZeroKeys<U>>;
+type StripZeroes<U extends Unit> = { [Dim in NonZeroKeys<U>]: U[Dim] };
 
+/** Gets the union of all dimensions of a unit with non zero or null exponents */
 type NonZeroKeys<U extends Unit> = { [Dim in keyof U]: NonNullable<U[Dim]> extends 0 ? never : Dim }[keyof U];
 
 /** Get the exponent at a given dimension of a unit, or 0 if that dimension is undefined */

diff --git a/src/quantity/quantities.ts b/src/quantity/quantities.ts
@@ -60,11 +60,11 @@ export const Frequency = Time.inverse();
 export type Frequency = typeof Frequency;
 
 /** 1 / s^2 */
-export const FrequencyDrift = Time.inverse().squared();
+export const FrequencyDrift = Time.toThe(-2);
 export type FrequencyDrift = typeof FrequencyDrift;
 
 /** 1 / m^2 */
-export const FuelEfficiency = Length.inverse().squared();
+export const FuelEfficiency = Length.toThe(-2);
 export type FuelEfficiency = typeof FuelEfficiency;
 
 /** 1 / m */
@@ -228,7 +228,7 @@ export const MagneticFlux = Energy.over(ElectricCurrent);
 export type MagneticFlux = typeof MagneticFlux;
 
 /** kg / (s^2 ⋅ A) */
-export const MagneticFluxDensity = Voltage.times(Time).over(Length.squared());
+export const MagneticFluxDensity = Voltage.times(Time).over(Area);
 export type MagneticFluxDensity = typeof MagneticFluxDensity;
 
 /** kg ⋅ m / (s^2 ⋅ A^2)  */