feat(optional): add validator for optional object

Author: TomokiMiyauci

combinator.ts

@@ -4,6 +4,7 @@
 import { TypeValidator } from "./validators/type.ts";
 import { InstanceValidator } from "./validators/instance.ts";
 import { DictionaryValidator } from "./validators/object/dictionary.ts";
+import { OptionalValidator } from "./validators/object/optional.ts";
 import { NullishValidator } from "./validators/nullish.ts";
 import { IntegerValidator } from "./validators/number/integer.ts";
 import { PositiveNumberValidator } from "./validators/number/positive_number.ts";
@@ -28,6 +29,7 @@ export const boolean = /* @__PURE__ */ new TypeValidator("boolean");
 export const instance = /* @__PURE__ */ lazy(InstanceValidator);
 export const type = /* @__PURE__ */ lazy(TypeValidator);
 export const object = /* @__PURE__ */ lazy(DictionaryValidator);
+export const optional = /* @__PURE__ */ lazy(OptionalValidator);
 export const nullish = /* @__PURE__ */ new NullishValidator();
 export const eq = /* @__PURE__ */ lazy(EqualityValidator);
 export const lt = /* @__PURE__ */ lazy(LessValidator);

deps.ts

@@ -1,7 +1,6 @@
 // Copyright 2023-latest Tomoki Miyauchi. All rights reserved. MIT license.
 // This module is browser compatible.
 
-export { isUndefined } from "https://deno.land/x/isx@1.3.1/is_undefined.ts";
 export { isEmpty } from "https://deno.land/x/isx@1.3.1/iterable/is_empty.ts";
 export { isNotEmpty } from "https://deno.land/x/isx@1.3.1/iterable/is_not_empty.ts";
 export { isNonNullable } from "https://deno.land/x/isx@1.3.1/is_non_nullable.ts";

mod.ts

@@ -20,6 +20,7 @@ export {
   nullish,
   number,
   object,
+  optional,
   pattern,
   positive,
   string,

validators/object/optional.ts

@@ -0,0 +1,36 @@
+// Copyright 2023-latest Tomoki Miyauchi. All rights reserved. MIT license.
+// This module is browser compatible.
+
+import { filterKeys } from "../../deps.ts";
+import { DictionaryValidator } from "./dictionary.ts";
+import {
+  Assert,
+  AssertiveValidator,
+  Validation,
+  ValidationError,
+} from "../../types.ts";
+
+export class OptionalValidator<
+  In extends Record<string, unknown> = Record<string, unknown>,
+  In_ extends In = In,
+> implements AssertiveValidator<Partial<In>, Partial<In_>> {
+  declare [Assert.symbol]: Partial<In_>;
+  constructor(
+    public validators:
+      & { [k in keyof In]: Validation<In[k], In_[k]> }
+      & { [k in keyof In_]: Validation<In_[k]> },
+  ) {}
+
+  *validate(input: Partial<In>): Iterable<ValidationError> {
+    const validators = filterKeys(
+      this.validators,
+      hasInput,
+    ) as typeof this.validators;
+
+    function hasInput(key: string): boolean {
+      return key in input;
+    }
+
+    yield* new DictionaryValidator<In, In_>(validators).validate(input as In);
+  }
+}