Dependent If Type

Author: sinclairzx81

example/index.ts

@@ -6,65 +6,17 @@ import Schema from 'typebox/schema'
 import Value from 'typebox/value'
 import Type from 'typebox'
 
-// ------------------------------------------------------------------
-// Settings
-// ------------------------------------------------------------------
+const A = Type.If(Type.Script('never'), Type.Literal('hello'), Type.Literal(1))
 
-System.Settings.Set({ enumerableKind: false })
+console.log(A)
 
-// ------------------------------------------------------------------
-// Guard
-// ------------------------------------------------------------------
+type A = Type.Static<typeof A>
+type B = Schema.XStatic<typeof A>
 
-const A = Guard.GraphemeCount('type-📦')      // 6
-const B = Guard.HasPropertyKey({ x: 1 }, 'x') // true
-
-// ------------------------------------------------------------------
-// Type
-// ------------------------------------------------------------------
-
-const T = Type.Object({
-  x: Type.Number(),
-  y: Type.Number(),
-  z: Type.Number()
-})
-
-// ------------------------------------------------------------------
-// Script
-// ------------------------------------------------------------------
-
-const S = Type.Script({ T }, `{
-  [K in keyof T]: T[K] | null
-}`)
-
-// ------------------------------------------------------------------
-// Infer
-// ------------------------------------------------------------------
-
-type T = Type.Static<typeof T>
-type S = Type.Static<typeof S>
-
-// ------------------------------------------------------------------
-// Parse
-// ------------------------------------------------------------------
-
-const R = Value.Parse(T, { x: 1, y: 2, z: 3 })
-
-// ------------------------------------------------------------------
-// Compile
-// ------------------------------------------------------------------
-const C = Compile(S)
-
-const X = C.Parse({ x: 1, y: 2, z: 3 })
-
-// ------------------------------------------------------------------
-// Format
-// ------------------------------------------------------------------
-
-const E = Format.IsEmail('user@domain.com')
-
-// ------------------------------------------------------------------
-// Schema
-// ------------------------------------------------------------------
-
-const D = Schema.Parse({ const: 'hello' }, 'hello')
+const X = Type.Script(`{
+  x: number with { description: 'hello' }
+  y: number
+  z: number  
+} & if { x: 1 } then { y: 2 } else
+    if { x: 2 } then { y: 3 }  
+`)

src/type/types/if.ts

@@ -0,0 +1,76 @@
+/*--------------------------------------------------------------------------
+
+TypeBox
+
+The MIT License (MIT)
+
+Copyright (c) 2017-2026 Haydn Paterson 
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+
+---------------------------------------------------------------------------*/
+
+// deno-fmt-ignore-file
+
+import { Memory } from '../../system/memory/index.ts'
+import { type StaticType, type StaticDirection } from './static.ts'
+import { type TSchema, type TSchemaOptions, IsKind } from './schema.ts'
+import { type TProperties } from './properties.ts'
+
+// ------------------------------------------------------------------
+// Static
+// ------------------------------------------------------------------
+export type StaticIf<Stack extends string[], Direction extends StaticDirection, Context extends TProperties, This extends TProperties, If extends TSchema, Then extends TSchema, Else extends TSchema,
+  StaticIf extends unknown = StaticType<Stack, Direction, Context, This, If>,
+  StaticThen extends unknown = StaticType<Stack, Direction, Context, This, Then>,
+  StaticElse extends unknown = StaticType<Stack, Direction, Context, This, Else>,
+  Result extends unknown = (StaticIf & StaticThen) | Exclude<StaticElse, StaticIf>
+> = Result
+// ------------------------------------------------------------------
+// Type
+// ------------------------------------------------------------------
+/** Represents a Conditionally Dependent If Type */
+export interface TIf<If extends TSchema = TSchema, Then extends TSchema = TSchema, Else extends TSchema = TSchema> extends TSchema {
+  '~kind': 'If'
+  if: If
+  then: Then
+  else: Else
+}
+// ------------------------------------------------------------------
+// Factory
+// ------------------------------------------------------------------
+/** Creates a Conditionally Dependent If Type */
+export function If<If extends TSchema, Then extends TSchema, Else extends TSchema>(if_: If, then_: Then, else_: Else, options: TSchemaOptions = {}): TIf<If, Then, Else> {
+  return Memory.Create({ '~kind': 'If' }, { if: if_, then: then_, else: else_ }, options) as never
+}
+// ------------------------------------------------------------------
+// Guard
+// ------------------------------------------------------------------
+/** Returns true if the given value is TIf. */
+export function IsIf(value: unknown): value is TIf {
+  return IsKind(value, 'If')
+}
+
+// ------------------------------------------------------------------
+// Options
+// ------------------------------------------------------------------
+/** Extracts options from a TIf. */
+export function IfOptions(type: TIf): TSchemaOptions {
+  return Memory.Discard(type, ['~kind', 'if', 'then', 'else'])
+}

src/type/types/index.ts

@@ -52,6 +52,7 @@ export * from './enum.ts'
 export * from './function.ts'
 export * from './generic.ts'
 export * from './identifier.ts'
+export * from './if.ts'
 export * from './infer.ts'
 export * from './integer.ts'
 export * from './intersect.ts'

src/type/types/static.ts

@@ -41,6 +41,7 @@ import type { StaticCyclic, TCyclic } from './cyclic.ts'
 import type { StaticEnum, TEnum, TEnumValue } from './enum.ts'
 import type { StaticFunction, TFunction } from './function.ts'
 import type { StaticInteger, TInteger } from './integer.ts'
+import type { StaticIf, TIf } from './if.ts'
 import type { StaticIntersect, TIntersect } from './intersect.ts'
 import type { StaticIterator, TIterator } from './iterator.ts'
 import type { StaticLiteral, TLiteral, TLiteralValue } from './literal.ts'
@@ -89,6 +90,7 @@ export type StaticType<Stack extends string[], Direction extends StaticDirection
   Type extends TConstructor<infer Parameters extends TSchema[], infer ReturnType extends TSchema> ? StaticConstructor<Stack, Direction, Context, This, Parameters, ReturnType> :
   Type extends TEnum<infer Values extends TEnumValue[]> ? StaticEnum<Values> :
   Type extends TFunction<infer Parameters extends TSchema[], infer ReturnType extends TSchema> ? StaticFunction<Stack, Direction, Context, This, Parameters, ReturnType> :
+  Type extends TIf<infer If extends TSchema, infer Then extends TSchema, infer Else extends TSchema> ? StaticIf<Stack, Direction, Context, This, If, Then, Else> :
   Type extends TInteger ? StaticInteger :
   Type extends TIntersect<infer Types extends TSchema[]> ? StaticIntersect<Stack, Direction, Context, This, Types> :
   Type extends TIterator<infer Types extends TSchema> ? StaticIterator<Stack, Direction, Context, This, Types> :

src/typebox.ts

@@ -95,6 +95,7 @@ export { Enum, IsEnum, type TEnum, type TEnumValue } from './type/types/enum.ts'
 export { Function, IsFunction, type TFunction } from './type/types/function.ts'
 export { Generic, IsGeneric, type TGeneric } from './type/types/generic.ts'
 export { Identifier, IsIdentifier, type TIdentifier } from './type/types/identifier.ts'
+export { If, IsIf, type TIf } from './type/types/if.ts'
 export { Infer, IsInfer, type TInfer } from './type/types/infer.ts'
 export { Integer, IsInteger, type TInteger } from './type/types/integer.ts'
 export { Intersect, IsIntersect, type TIntersect } from './type/types/intersect.ts'