Support typescript 2.9 (#31)

package.json

@@ -27,6 +27,6 @@
         "tslint-config-standard": "^7.0.0",
         "tslint-no-circular-imports": "^0.4.0",
         "tslint-plugin-prettier": "^1.3.0",
-        "typescript": "~2.8.3"
+        "typescript": "~2.9.1"
     }
 }

src/measure/types.ts

@@ -37,7 +37,7 @@ export type NthRootableUnit<N extends Exponent> = Partial<{
 /** Handle errors in the result of an arithmetic operation. */
 export type HandleErrors<Result extends ArithmeticResult> = true extends ResultHasError<Result>
     ? ArithmeticError
-    : Clean<StripZeroes<RemoveErrors<Result>>>;
+    : StripZeroes<RemoveErrors<Result>>;
 
 export type ResultHasError<Result> = { [Dim in keyof Result]: IsArithmeticError<Result[Dim]> }[keyof Result];
 
@@ -49,14 +49,11 @@ export type ArithmeticResult = { [dimension: string]: Exponent | ArithmeticError
 
 // Utility types
 
-/** Ensures that a type will be displayed nicely in editors / compiler output */
-export type Clean<T> = { [K in keyof T]: T[K] };
-
 /** Removes all zero exponent dimensions from a dimension vector */
 export type StripZeroes<U extends Unit> = Pick<U, NonZeroKeys<U>>;
 
 export type NonZeroKeys<U extends Unit> = { [Dim in keyof U]: U[Dim] extends 0 ? never : Dim }[keyof U];
 
-export type GetExponent<U extends Unit, K extends string> = K extends keyof Unit
+export type GetExponent<U extends Unit, K> = K extends keyof Unit
     ? (undefined extends U[K] ? 0 : NonNullable<U[K]>)
     : 0;

yarn.lock

@@ -3369,9 +3369,9 @@ type-check@~0.3.2:
   dependencies:
     prelude-ls "~1.1.2"
 
-typescript@~2.8.3:
-  version "2.8.3"
-  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.8.3.tgz#5d817f9b6f31bb871835f4edf0089f21abe6c170"
+typescript@~2.9.1:
+  version "2.9.2"
+  resolved "https://registry.yarnpkg.com/typescript/-/typescript-2.9.2.tgz#1cbf61d05d6b96269244eb6a3bce4bd914e0f00c"
 
 uglify-js@^2.6:
   version "2.8.29"