API Reference / @evolu/common / Type / UnionType

Interface: UnionType<Members>

Defined in: packages/common/src/Type.ts:2946

UnionType extends Type with an additional members property for reflection.

Extends

• Type<"Union", InferType<Members[number]>, InferInput<Members[number]>, UnionError<InferErrors<Members[number]>>, InferInput<Members[number]>, never>

Type Parameters

Type Parameter
Members extends [AnyType, ...ReadonlyArray<AnyType>]

Properties

Property	Modifier	Type	Description	Inherited from	Defined in
[EvoluTypeSymbol]	readonly	true	-	Type.[EvoluTypeSymbol]	packages/common/src/Type.ts:171
Error	public	UnionError<InferErrors<Members[number]>>	The specific error introduced by this Type. ### Example type StringError = typeof String.Error;	Type.Error	packages/common/src/Type.ts:96
Errors	readonly	UnionError<InferErrors<Members[number]>>	Error	ParentError ### Example type StringParentErrors = typeof String.Errors;	Type.Errors
from	readonly	(value) => Result<InferType<Members[number]>, UnionError<InferErrors<Members[number]>>>	Creates T from an Input value. This is useful when we have a typed value. from is a typed alias of fromUnknown.	Type.from	packages/common/src/Type.ts:111
fromParent	readonly	(value) => Result<InferType<Members[number]>, UnionError<InferErrors<Members[number]>>>	Creates T from Parent type. This function skips parent Types validations/transformations when we have already partially validated/transformed value. For example, TrimString.from checks whether a value is a string and trims it. If we only want to trim a string, we can use fromParent. ### Example // string & Brand<"Trimmed"> const value = TrimString.fromParent("a ").value; // as efficient as foo.trim()	Type.fromParent	packages/common/src/Type.ts:145
fromUnknown	readonly	(value) => Result<InferType<Members[number]>, UnionError<InferErrors<Members[number]>>>	Creates T from an unknown value. This is useful when a value is unknown.	Type.fromUnknown	packages/common/src/Type.ts:118
Input	public	InferInput<Members[number]>	The type expected by from and fromUnknown. ### Example type StringInput = typeof String.Input;	Type.Input	packages/common/src/Type.ts:94
is	readonly	(value) => value is InferType<Members[number]>	A type guard that checks whether an unknown value satisfies the Type. ### Example const value: unknown = "hello"; if (String.is(value)) { // TypeScript now knows valueis astring here. console.log("This is a valid string!"); } const strings: unknown[] = [1, "hello", true, "world"]; const filteredStrings = strings.filter(String.is); console.log(filteredStrings); // ["hello", "world"]	Type.is	packages/common/src/Type.ts:169
members	readonly	Members	-	-	packages/common/src/Type.ts:2955
name	readonly	"Union"	-	Type.name	packages/common/src/Type.ts:102
Parent	public	InferInput<Members[number]>	The parent type. ### Example type StringParent = typeof String.Parent;	Type.Parent	packages/common/src/Type.ts:98
ParentError	public	never	The parent's error. ### Example type StringParentError = typeof String.ParentError;	Type.ParentError	packages/common/src/Type.ts:100
to	readonly	(value) => InferInput	The opposite of from and fromUnknown. This is useful to transform T back to its Input representation. For refine, it only removes the brand. For transform, it changes value.	Type.to	packages/common/src/Type.ts:127
toParent	readonly	(value) => InferInput	The opposite of fromParent.	Type.toParent	packages/common/src/Type.ts:148
Type	readonly	InferType	The type this Type resolves to. ### Example type String = typeof String.Type;	Type.Type	packages/common/src/Type.ts:182