fix: several issues with ts schema generation (#62)

* fix: several issues with ts schema generation

* addressing review comments

Author: ymc9

packages/sdk/src/ts-schema-generator.ts

@@ -618,17 +618,18 @@ export class TsSchemaGenerator {
                     ts.factory.createPropertyAssignment(
                         field.name,
                         ts.factory.createObjectLiteralExpression([
-                            ts.factory.createPropertyAssignment(
-                                'type',
-                                ts.factory.createStringLiteral(field.type.type!),
-                            ),
+                            ts.factory.createPropertyAssignment('type', this.generateFieldTypeLiteral(field)),
                         ]),
                     ),
                 );
             }
         }
 
         // model-level id and unique
+
+        // it's possible to have the same set of fields in both `@@id` and `@@unique`
+        // so we need to deduplicate them
+        const seenKeys = new Set<string>();
         for (const attr of dm.attributes) {
             if (attr.decl.$refText === '@@id' || attr.decl.$refText === '@@unique') {
                 const fieldNames = this.getReferenceNames(attr.args[0]!.value);
@@ -643,15 +644,17 @@ export class TsSchemaGenerator {
                         ts.factory.createPropertyAssignment(
                             fieldNames[0]!,
                             ts.factory.createObjectLiteralExpression([
-                                ts.factory.createPropertyAssignment(
-                                    'type',
-                                    ts.factory.createStringLiteral(fieldDef.type.type!),
-                                ),
+                                ts.factory.createPropertyAssignment('type', this.generateFieldTypeLiteral(fieldDef)),
                             ]),
                         ),
                     );
                 } else {
                     // multi-field unique
+                    const key = fieldNames.join('_');
+                    if (seenKeys.has(key)) {
+                        continue;
+                    }
+                    seenKeys.add(key);
                     properties.push(
                         ts.factory.createPropertyAssignment(
                             fieldNames.join('_'),
@@ -663,7 +666,7 @@ export class TsSchemaGenerator {
                                         ts.factory.createObjectLiteralExpression([
                                             ts.factory.createPropertyAssignment(
                                                 'type',
-                                                ts.factory.createStringLiteral(fieldDef.type.type!),
+                                                this.generateFieldTypeLiteral(fieldDef),
                                             ),
                                         ]),
                                     );
@@ -678,6 +681,11 @@ export class TsSchemaGenerator {
         return ts.factory.createObjectLiteralExpression(properties, true);
     }
 
+    private generateFieldTypeLiteral(field: DataModelField): ts.Expression {
+        invariant(field.type.type || field.type.reference, 'Field type must be a primitive or reference');
+        return ts.factory.createStringLiteral(field.type.type ?? field.type.reference!.$refText);
+    }
+
     private createEnumObject(e: Enum) {
         return ts.factory.createObjectLiteralExpression(
             e.fields.map((field) =>