feat: adding default values (#26)

Author: mvhenten

src/emitter.ts

@@ -8,6 +8,7 @@ import type {
 	Scalar,
 	Type,
 	Union,
+	Value,
 } from "@typespec/compiler";
 import {
 	type EmitContext,
@@ -21,6 +22,29 @@ import * as ts from "typescript";
 import { StateKeys } from "./lib.js";
 import { RawCode, stringifyObject } from "./stringify.js";
 
+/**
+ * Extracts a primitive default value from a TypeSpec Value.
+ * Returns undefined if the value cannot be converted to a simple default.
+ */
+function extractDefaultValue(
+	value: Value,
+): string | number | boolean | undefined {
+	switch (value.valueKind) {
+		case "StringValue":
+			return value.value;
+		case "NumericValue":
+			return Number(value.value.asNumber());
+		case "BooleanValue":
+			return value.value;
+		case "EnumValue":
+			// For enum values, use the value if specified, otherwise use the member name
+			return value.value.value ?? value.value.name;
+		default:
+			// Complex values (objects, arrays) are not supported as simple defaults
+			return undefined;
+	}
+}
+
 function emitIntrinsincScalar(type: Scalar) {
 	switch (type.name) {
 		case "boolean":
@@ -225,10 +249,21 @@ function emitType(type: Type): Attribute {
 }
 
 function emitModelProperty(prop: ModelProperty): Attribute {
-	return {
+	const attr: Attribute = {
 		...emitType(prop.type),
 		required: !prop.optional,
 	};
+
+	// Add default value if present
+	if (prop.defaultValue) {
+		const defaultValue = extractDefaultValue(prop.defaultValue);
+		if (defaultValue !== undefined) {
+			// @ts-expect-error - default is a valid ElectroDB attribute property
+			attr.default = defaultValue;
+		}
+	}
+
+	return attr;
 }
 
 const getLabel = (ctx: EmitContext, prop: ModelProperty) =>
@@ -274,6 +309,15 @@ function emitAttribute(ctx: EmitContext, prop: ModelProperty): Attribute {
 		attr.label = label;
 	}
 
+	// Add default value if present
+	if (prop.defaultValue) {
+		const defaultValue = extractDefaultValue(prop.defaultValue);
+		if (defaultValue !== undefined) {
+			// @ts-expect-error - default is a valid ElectroDB attribute property
+			attr.default = defaultValue;
+		}
+	}
+
 	return attr;
 }
 

test/entities.test.js

@@ -1,6 +1,6 @@
 import assert from "node:assert/strict";
 import { suite, test } from "node:test";
-import { Job, Person } from "../build/entities/index.js";
+import { Job, Person, Task } from "../build/entities/index.js";
 
 suite("Job Entity", () => {
 	test("Job entity has correct model configuration", () => {
@@ -53,6 +53,86 @@ suite("Job Entity", () => {
 	});
 });
 
+suite("Task Entity - Default Values", () => {
+	test("Task entity has correct model configuration", () => {
+		assert.deepEqual(Task.model, {
+			entity: "task",
+			service: "org",
+			version: "1",
+		});
+	});
+
+	suite("String default values", () => {
+		test("optional description has string default", () => {
+			assert.deepEqual(Task.attributes.description, {
+				type: "string",
+				required: false,
+				default: "No description provided",
+			});
+		});
+	});
+
+	suite("Enum default values", () => {
+		test("priority has enum default value", () => {
+			assert.deepEqual(Task.attributes.priority, {
+				type: ["LOW", "MEDIUM", "HIGH"],
+				required: true,
+				default: "MEDIUM",
+			});
+		});
+	});
+
+	suite("Number default values", () => {
+		test("count has number default value", () => {
+			assert.deepEqual(Task.attributes.count, {
+				type: "number",
+				required: true,
+				default: 0,
+			});
+		});
+	});
+
+	suite("Boolean default values", () => {
+		test("active has boolean default value", () => {
+			assert.deepEqual(Task.attributes.active, {
+				type: "boolean",
+				required: true,
+				default: true,
+			});
+		});
+	});
+
+	suite("Nested model default values", () => {
+		test("settings is a list type", () => {
+			assert.equal(Task.attributes.settings.type, "list");
+			assert.equal(Task.attributes.settings.items.type, "map");
+		});
+
+		test("settings item value property has string default", () => {
+			assert.deepEqual(Task.attributes.settings.items.properties.value, {
+				type: "string",
+				required: true,
+				default: "default",
+			});
+		});
+
+		test("settings item enabled property has boolean default", () => {
+			assert.deepEqual(Task.attributes.settings.items.properties.enabled, {
+				type: "boolean",
+				required: true,
+				default: true,
+			});
+		});
+
+		test("settings item key property has no default", () => {
+			assert.deepEqual(Task.attributes.settings.items.properties.key, {
+				type: "string",
+				required: true,
+			});
+		});
+	});
+});
+
 suite("Person Entity", () => {
 	test("Person entity has correct model configuration", () => {
 		assert.deepEqual(Person.model, {
@@ -195,13 +275,10 @@ suite("Person Entity", () => {
 		});
 
 		test("contact item has description property", () => {
-			assert.deepEqual(
-				Person.attributes.contact.items.properties.description,
-				{
-					type: "string",
-					required: true,
-				},
-			);
+			assert.deepEqual(Person.attributes.contact.items.properties.description, {
+				type: "string",
+				required: true,
+			});
 		});
 	});
 
@@ -239,13 +316,10 @@ suite("Person Entity", () => {
 		});
 
 		test("additionalInfo item has name property as string", () => {
-			assert.deepEqual(
-				Person.attributes.additionalInfo.items.properties.name,
-				{
-					type: "string",
-					required: true,
-				},
-			);
+			assert.deepEqual(Person.attributes.additionalInfo.items.properties.name, {
+				type: "string",
+				required: true,
+			});
 		});
 
 		test("additionalInfo item value property uses CustomAttributeType for union", () => {

test/main.tsp

@@ -67,6 +67,35 @@ model Job {
     description: string;
 }
 
+enum Priority {
+    LOW,
+    MEDIUM,
+    HIGH,
+}
+
+model SettingsItem {
+    key: string;
+    value: string = "default";
+    enabled: boolean = true;
+}
+
+@entity("task", "org")
+@index(
+    "tasks",
+    {
+        pk: [Task.pk],
+    }
+)
+model Task {
+    pk: UUID;
+    title: string;
+    description?: string = "No description provided";
+    priority: Priority = Priority.MEDIUM;
+    count: int32 = 0;
+    active: boolean = true;
+    settings: SettingsItem[];
+}
+
 @entity("person", "org")
 @index(
     "persons",