feat(typescript-types): Add Simplify<T, E, I>

packages/typescript-types/test/simplify.tst.ts

@@ -0,0 +1,44 @@
+import type { Simplify } from '@/simplify.js'
+import { expect } from 'tstyche'
+
+type TyreSize = {
+	radius: number
+	type: 'winter' | 'summer'
+}
+
+type Maker = {
+	maker: string
+}
+
+type TyreMaker = Maker & TyreSize
+
+type SimplifiedTyreMaker = {
+	radius: number
+	type: 'winter' | 'summer'
+	maker: string
+}
+
+expect<TyreMaker>().type.not.toBe<SimplifiedTyreMaker>()
+expect<Simplify<TyreMaker>>().type.toBe<SimplifiedTyreMaker>()
+
+type Train = {
+	wheels: TyreMaker[]
+}
+
+type SimplifiedTrain = {
+	wheels: SimplifiedTyreMaker[]
+}
+
+expect<Train>().type.not.toBe<SimplifiedTrain>()
+expect<Simplify<Train>>().type.toBe<SimplifiedTrain>()
+
+type Car = {
+	wheels: [TyreMaker, TyreMaker]
+}
+
+type SimplifiedCar = {
+	wheels: [SimplifiedTyreMaker, SimplifiedTyreMaker]
+}
+
+expect<Car>().type.not.toBe<SimplifiedCar>()
+expect<Simplify<Car>>().type.toBe<SimplifiedCar>()