break(object): add additionalProperties: false if properties

Closes #5

mod.test.ts

@@ -417,13 +417,59 @@ describe('Object', () => {
 		});
 	});
 
+	describe('additionalProperties', () => {
+		it('should NOT be added for object w/o properties', () => {
+			let output = t.object();
+
+			assertEquals(output, {
+				type: 'object',
+				properties: undefined,
+			});
+		});
+
+		it('should be added for object w/ defined properties', () => {
+			let output = t.object({
+				name: t.string(),
+			});
+
+			assertEquals(output, {
+				type: 'object',
+				additionalProperties: false, // <<
+				required: ['name'],
+				properties: {
+					name: {
+						type: 'string',
+					},
+				},
+			});
+		});
+
+		it('should allow override via options', () => {
+			let output = t.object({
+				name: t.string(),
+			}, {
+				additionalProperties: true,
+			});
+
+			assertEquals(output, {
+				type: 'object',
+				additionalProperties: true, // <<
+				required: ['name'],
+				properties: {
+					name: {
+						type: 'string',
+					},
+				},
+			});
+		});
+	});
+
 	it('should build "properties" property', () => {
 		let output = t.object({
 			name: t.string(),
 			age: t.integer(),
 		}, {
 			description: 'person',
-			additionalProperties: false,
 			examples: [{
 				name: 'lukeed',
 				age: 123,
@@ -464,6 +510,7 @@ describe('Object', () => {
 
 		assertEquals(output, {
 			type: 'object',
+			additionalProperties: false,
 			properties: {
 				name: { type: 'string' },
 				age: { type: 'integer' },
@@ -477,11 +524,6 @@ describe('Object', () => {
 			name: t.string(),
 			age: t.optional(t.integer()),
 		});
-		// TODO: Make ^ this:
-		//   t.Object<{
-		//     name: t.String<string>;
-		//     age?: t.Integer<number>;
-		//   }>
 
 		// NOTE: age has OPTIONAL symbol
 		// This is dropped natively in JSON
@@ -491,13 +533,19 @@ describe('Object', () => {
 
 		assertEquals(copy, {
 			type: 'object',
+			additionalProperties: false,
 			properties: {
 				name: { type: 'string' },
 				age: { type: 'integer' },
 			},
 			required: ['name'], // <<
 		});
 	});
+
+	it('should default "additionalProperties" to false', () => {
+		let output = t.object();
+		type X = t.Infer<typeof output>;
+	});
 });
 
 // ---

mod.ts

@@ -551,6 +551,14 @@ type _object<T extends Properties> = Annotations & {
  * > Use {@link optional} to mark individual properties as optional, or supply
  * > your own `required` attribute.
  *
+ * > [!IMPORTANT]
+ * > By default, `additionalProperties: false` is added when `properties` are defined.
+ * > This restricts the object's definition to **only** accept the property fields you've defined.
+ * > Otherwise, when no `properties` are defined — for example, `t.object()` — then
+ * > `additionalProperties: false` **is not** added, which allows for extra
+ * > properties. You may explicitly control this setting via
+ * > `options.additionalProperties` at any time.
+ *
  * @example Basic Usage
  * ```ts
  * let pet = t.object({
@@ -573,11 +581,47 @@ type _object<T extends Properties> = Annotations & {
  *   name: t.string(),
  *   age: t.integer(),
  * }, {
- *   additionalProperties: false,
  *   description: 'the Pet schema',
  *   // ...
  * });
  * ```
+ *
+ * @example Additional Properties
+ * ```ts
+ * // Accept any object
+ * // AKA: any object w/ any properties
+ * let a = t.object();
+ * //-> { type: "object" }
+ *
+ * // Accept a specific object
+ * // AKA: only specified properites
+ * let b = t.object({
+ *   name: t.string(),
+ * });
+ * //-> {
+ * //->   type: "object",
+ * //->   additionalProperties: false,
+ * //->   required: ["name"],
+ * //->   properties: {
+ * //->     name: { type: "string" }
+ * //->   }
+ * //-> }
+ *
+ * // Accept a specific object
+ * // ... but allow extra properties
+ * let c = t.object({
+ *   name: t.string(),
+ * }, {
+ *   additionalProperties: true,
+ * });
+ * //-> {
+ * //->   type: "object",
+ * //->   additionalProperties: true,
+ * //->   required: ["name"],
+ * //->   properties: {
+ * //->     name: { type: "string" }
+ * //->   }
+ * //-> }
  */
 function _object<
 	P extends Properties,
@@ -592,19 +636,23 @@ function _object<
 		properties,
 	} as T;
 
-	if (properties && !o.required) {
-		let k: keyof P;
-		let arr: (keyof P)[] = [];
-		for (k in properties) {
-			if (properties[k][OPTIONAL]) {
-				// NOTE: delete = deopt
-				properties[k][OPTIONAL] = undefined;
-			} else {
-				arr.push(k);
+	if (properties) {
+		o.additionalProperties ||= false;
+
+		if (!o.required) {
+			let k: keyof P;
+			let arr: (keyof P)[] = [];
+			for (k in properties) {
+				if (properties[k][OPTIONAL]) {
+					// NOTE: delete = deopt
+					properties[k][OPTIONAL] = undefined;
+				} else {
+					arr.push(k);
+				}
+			}
+			if (arr.length > 0) {
+				o.required = arr;
 			}
-		}
-		if (arr.length > 0) {
-			o.required = arr;
 		}
 	}
 

readme.md

@@ -1,6 +1,6 @@
 # tschema [![CI](https://github.com/lukeed/tschema/workflows/CI/badge.svg)](https://github.com/lukeed/tschema/actions?query=workflow%3ACI) [![licenses](https://licenses.dev/b/npm/tschema)](https://licenses.dev/npm/tschema)
 
-> A tiny (408b) utility to build [JSON schema](https://json-schema.org/understanding-json-schema/reference) types.
+> A tiny (425b) utility to build [JSON schema](https://json-schema.org/understanding-json-schema/reference) types.
 
 ## Install
 

scripts/build.ts

@@ -1,7 +1,7 @@
 import { join, resolve } from 'jsr:@std/path@^1.0';
 import oxc from 'npm:oxc-transform@^0.23';
 
-const bytes = 408;
+const bytes = 425;
 
 const version = Deno.args[0];
 console.log('? version:', version);