feat(s.object): add passthrough (#66)

README.md

@@ -335,6 +335,10 @@ person.parse({
 
 You can use the `.ignore` getter to reset an object schema to the default behaviour (ignoring unrecognized keys).
 
+##### `.passthrough`
+
+You can use the `.passthrough` getter to make the validator add the unrecognized properties the shape does not have, from the input.
+
 #### Records
 
 Record schemas are similar to objects, but validate `Record<string, T>` types, keep in mind this does not check for the keys, and cannot support validation for specific ones:

src/validators/ObjectValidator.ts

@@ -32,6 +32,9 @@ export class ObjectValidator<T extends NonNullObject> extends BaseValidator<T> {
 				this.handleStrategy = (value) => this.handleStrictStrategy(value);
 				break;
 			}
+			case ObjectValidatorStrategy.Passthrough:
+				this.handleStrategy = (value) => this.handlePassthroughStrategy(value);
+				break;
 		}
 	}
 
@@ -43,6 +46,10 @@ export class ObjectValidator<T extends NonNullObject> extends BaseValidator<T> {
 		return Reflect.construct(this.constructor, [this.shape, ObjectValidatorStrategy.Ignore, this.constraints]);
 	}
 
+	public get passthrough(): this {
+		return Reflect.construct(this.constructor, [this.shape, ObjectValidatorStrategy.Passthrough, this.constraints]);
+	}
+
 	public get partial(): ObjectValidator<{ [Key in keyof T]?: T[Key] }> {
 		const shape = Object.fromEntries(this.keys.map((key) => [key, this.shape[key].optional]));
 		return Reflect.construct(this.constructor, [shape, this.strategy, this.constraints]);
@@ -138,9 +145,15 @@ export class ObjectValidator<T extends NonNullObject> extends BaseValidator<T> {
 			? Result.ok(finalResult)
 			: Result.err(new CombinedPropertyError(errors));
 	}
+
+	private handlePassthroughStrategy(value: NonNullObject): Result<T, CombinedPropertyError> {
+		const result = this.handleIgnoreStrategy(value);
+		return result.isErr() ? result : Result.ok({ ...value, ...result.value } as T);
+	}
 }
 
 export const enum ObjectValidatorStrategy {
 	Ignore,
-	Strict
+	Strict,
+	Passthrough
 }

tests/validators/object.test.ts

@@ -97,7 +97,7 @@ describe('ObjectValidator', () => {
 	});
 
 	describe('Ignore', () => {
-		const ignorePredicate = predicate.strict.ignore;
+		const ignorePredicate = predicate.ignore;
 
 		test('GIVEN matching keys and values THEN returns no errors', () => {
 			expect(ignorePredicate.parse({ username: 'Sapphire', password: 'helloworld', email: '[email protected]' })).toStrictEqual({
@@ -114,6 +114,25 @@ describe('ObjectValidator', () => {
 		});
 	});
 
+	describe('Passthrough', () => {
+		const passthroughPredicate = predicate.passthrough;
+
+		test('GIVEN matching keys and values THEN returns no errors', () => {
+			expect(passthroughPredicate.parse({ username: 'Sapphire', password: 'helloworld', email: '[email protected]' })).toStrictEqual({
+				email: '[email protected]',
+				username: 'Sapphire',
+				password: 'helloworld'
+			});
+		});
+
+		test('GIVEN missing keys THEN throws CombinedPropertyError with MissingPropertyError', () => {
+			expectError(
+				() => passthroughPredicate.parse({ username: 'Sapphire' }),
+				new CombinedPropertyError([['password', new MissingPropertyError('password')]])
+			);
+		});
+	});
+
 	describe('Partial', () => {
 		const partialPredicate = predicate.partial;