Generate PlainDate as a Date instead of as a string

packages/typespec-test/test/healthInsights_radiologyinsights/generated/typespec-ts/review/health-insights-radiologyinsights.api.md

@@ -347,7 +347,7 @@ export interface PatientDocument {
 
 // @public
 export interface PatientInfo {
-    birthDate?: string;
+    birthDate?: Date;
     clinicalInfo?: Resource[];
     sex?: PatientInfoSex;
 }

packages/typespec-test/test/healthInsights_radiologyinsights/generated/typespec-ts/src/models/models.ts

@@ -53,15 +53,17 @@ export interface PatientInfo {
   /** The patient's sex. */
   sex?: PatientInfoSex;
   /** The patient's date of birth. */
-  birthDate?: string;
+  birthDate?: Date;
   /** Known clinical information for the patient, structured. */
   clinicalInfo?: Resource[];
 }
 
 export function patientInfoSerializer(item: PatientInfo): any {
   return {
     sex: item["sex"],
-    birthDate: item["birthDate"],
+    birthDate: !item["birthDate"]
+      ? item["birthDate"]
+      : item["birthDate"].toISOString().split("T")[0],
     clinicalInfo: !item["clinicalInfo"]
       ? item["clinicalInfo"]
       : resourceArraySerializer(item["clinicalInfo"]),

packages/typespec-ts/src/modular/emitSamples.ts

@@ -517,6 +517,7 @@ function getParameterValue(
   switch (value.kind) {
     case "string": {
       switch (value.type.kind) {
+        case "plainDate":
         case "utcDateTime":
           retValue = `new Date("${value.value}")`;
           break;

packages/typespec-ts/src/modular/helpers/operationHelpers.ts

@@ -1722,6 +1722,9 @@ export function serializeRequestValue(
       ? `!${clientValue}? ${clientValue}: `
       : "";
   switch (type.kind) {
+    case "plainDate":
+      // plainDate always uses ISO8601 format (YYYY-MM-DD)
+      return `${nullOrUndefinedPrefix}${clientValue}.toISOString().split('T')[0]`;
     case "utcDateTime":
       switch (type.encode ?? format) {
         case "rfc7231":
@@ -1849,6 +1852,9 @@ export function deserializeResponseValue(
       ? `!${restValue}? ${restValue}: `
       : "";
   switch (type.kind) {
+    case "plainDate":
+      // plainDate deserializes from YYYY-MM-DD string to Date
+      return `${nullOrUndefinedPrefix} new Date(${restValue})`;
     case "utcDateTime":
       return `${nullOrUndefinedPrefix} new Date(${type.encode === "unixTimestamp" ? `${restValue} * 1000` : restValue})`;
     case "array": {

packages/typespec-ts/src/modular/helpers/typeHelpers.ts

@@ -78,7 +78,7 @@ const NumericTypeKinds = [
   "decimal128"
 ];
 
-const DateTimeTypeKinds = ["plainDate", "plainTime"];
+const DateTimeTypeKinds = ["plainTime"];
 
 // This may be a good candidate to move to TCGC
 export function isNumericTypeKind(kind: string): boolean {

packages/typespec-ts/src/modular/serialization/serializeUtils.ts

@@ -81,6 +81,7 @@ export function isSpecialUnionVariant(
 
   if (
     t.kind === "utcDateTime" ||
+    t.kind === "plainDate" ||
     t.kind === "bytes" ||
     (t.kind === "model" &&
       t.properties

packages/typespec-ts/src/modular/type-expressions/get-type-expression.ts

@@ -62,7 +62,6 @@ export function getTypeExpression(
       }
       return "number";
     case "endpoint":
-    case "plainDate":
     case "plainTime":
     case "string":
     case "url":
@@ -103,6 +102,7 @@ export function getTypeExpression(
     case "union":
       return getUnionExpression(context, type, options);
     case "utcDateTime":
+    case "plainDate":
       return "Date";
 
     default:

packages/typespec-ts/test/azureModularIntegration/generated/type/property/optionality/src/index.d.ts

@@ -225,7 +225,7 @@ export declare interface PlainDateOperations {
 }
 
 export declare interface PlainDateProperty {
-    property?: string;
+    property?: Date;
 }
 
 export declare interface PlainDatePutAllOptionalParams extends OperationOptions {

packages/typespec-ts/test/azureModularIntegration/optionalProperties.spec.ts

@@ -84,7 +84,7 @@ describe("OptionalProperties Modular Client", () => {
   });
 
   it("should handle optional plainDate", async () => {
-    const testValue = "2022-12-12";
+    const testValue = new Date("2022-12-12");
     const result = await client.plainDate.getAll();
     assert.deepEqual(result.property, testValue);
     const result2 = await client.plainDate.getDefault();

packages/typespec-ts/test/modularIntegration/generated/type/property/optionality/src/index.d.ts

@@ -225,7 +225,7 @@ export declare interface PlainDateOperations {
 }
 
 export declare interface PlainDateProperty {
-    property?: string;
+    property?: Date;
 }
 
 export declare interface PlainDatePutAllOptionalParams extends OperationOptions {

packages/typespec-ts/test/modularIntegration/optionalProperties.spec.ts

@@ -84,7 +84,7 @@ describe("OptionalProperties Modular Client", () => {
   });
 
   it("should handle optional plainDate", async () => {
-    const testValue = "2022-12-12";
+    const testValue = new Date("2022-12-12");
     const result = await client.plainDate.getAll();
     assert.deepEqual(result.property, testValue);
     const result2 = await client.plainDate.getDefault();

packages/typespec-ts/test/modularUnit/scenarios/modelsGenerator/modelsGenerator.md

@@ -411,7 +411,7 @@ op read(@body body: Foo): { @body body: Foo };
 /* eslint-disable @typescript-eslint/explicit-module-boundary-types */
 /** model interface Foo */
 export interface Foo {
-  prop1: string;
+  prop1: Date;
   prop2: string;
   prop3: Date;
   prop4: string;
@@ -423,7 +423,7 @@ export interface Foo {
 ```ts models function fooSerializer
 export function fooSerializer(item: Foo): any {
   return {
-    prop1: item["prop1"],
+    prop1: item["prop1"].toISOString().split('T')[0],
     prop2: item["prop2"],
     prop3: item["prop3"].toISOString(),
     prop4: item["prop4"],
@@ -436,7 +436,7 @@ export function fooSerializer(item: Foo): any {
 ```ts models function fooDeserializer
 export function fooDeserializer(item: any): Foo {
   return {
-    prop1: item["prop1"],
+    prop1: new Date(item["prop1"]),
     prop2: item["prop2"],
     prop3: new Date(item["prop3"]),
     prop4: item["prop4"],

packages/typespec-ts/test/modularUnit/scenarios/samples/parameters/parameterTypesCheck.md

@@ -131,7 +131,7 @@ async function read(): Promise<void> {
     stringLiteral: "foo",
     booleanLiteral: true,
     numberLiteral: 12,
-    plainDateProp: "2022-12-12",
+    plainDateProp: new Date("2022-12-12"),
     plainTimeProp: "13:06:12",
     utcDateTimeProp: new Date("2022-08-26T18:38:00Z"),
     offsetDateTimeProp: "2022-08-26T18:38:00Z",