feat: add default option

Co-authored-by: imdudu1 <cd80@kakao.com>

Author: jbl428

lib/builders/request-param.builder.spec.ts

@@ -14,6 +14,18 @@ describe('RequestParamBuilder', () => {
     expect(actual).toBe('?keyword=search');
   });
 
+  test('should build query string with explicit key and default', () => {
+    // given
+    const builder = new RequestParamBuilder(0, 'keyword', 'default');
+    const args = [null];
+
+    // when
+    const actual = builder.build(args);
+
+    // then
+    expect(actual).toBe('?keyword=default');
+  });
+
   test('should build query string without key', () => {
     // given
     const builder = new RequestParamBuilder(1);

lib/builders/request-param.builder.ts

@@ -2,21 +2,26 @@ import querystring from 'node:querystring';
 import { TupleArrayBuilder } from './tuple-array.builder';
 
 export class RequestParamBuilder {
-  metadata: Array<[index: number, key: string | undefined]> = [];
+  metadata: Array<
+    [
+      index: number,
+      value: [key: string | undefined, defaultValue: string | undefined],
+    ]
+  > = [];
 
-  constructor(index: number, key?: string) {
-    this.add(index, key);
+  constructor(index: number, key?: string, defaultValue?: string) {
+    this.add(index, key, defaultValue);
   }
 
-  add(index: number, key?: string): void {
-    this.metadata.push([index, key]);
+  add(index: number, key?: string, defaultValue?: string): void {
+    this.metadata.push([index, [key, defaultValue]]);
   }
 
   build(args: any[]): string {
     const result = this.metadata.reduce<Record<string, any>>(
-      (acc, [index, key]) => {
+      (acc, [index, [key, defaultValue]]) => {
         if (key != null) {
-          acc[key] = String(args[index]);
+          acc[key] = String(args[index] ?? defaultValue ?? '');
           return acc;
         }
 

lib/decorators/request-param.decorator.spec.ts

@@ -40,7 +40,7 @@ describe('RequestParam', () => {
 
     // then
     expect(result.metadata).toHaveLength(1);
-    expect(result.metadata[0]).toEqual([0, undefined]);
+    expect(result.metadata[0]).toEqual([0, [undefined, undefined]]);
   });
 
   test('should set request param metadata with key', () => {
@@ -60,14 +60,14 @@ describe('RequestParam', () => {
 
     // then
     expect(result.metadata).toHaveLength(1);
-    expect(result.metadata[0]).toEqual([1, 'bar']);
+    expect(result.metadata[0]).toEqual([1, ['bar', undefined]]);
   });
 
   test('should set request param metadata with multiple decorator', () => {
     // given
     class TestService {
       request(
-        @RequestParam('foo') foo: string,
+        @RequestParam('foo', 'default') foo: string,
         @RequestParam() bar: { bar: string },
       ): string {
         return foo;
@@ -83,8 +83,8 @@ describe('RequestParam', () => {
 
     // then
     expect(result.metadata).toEqual([
-      [1, undefined],
-      [0, 'foo'],
+      [1, [undefined, undefined]],
+      [0, ['foo', 'default']],
     ]);
   });
 });

lib/decorators/request-param.decorator.ts

@@ -1,7 +1,15 @@
 import { REQUEST_PARAM_METADATA } from './constants';
 import { RequestParamBuilder } from '../builders/request-param.builder';
 
-export function RequestParam(key?: string): ParameterDecorator {
+export function RequestParam(key?: string): ParameterDecorator;
+export function RequestParam(
+  key: string,
+  defaultValue?: string,
+): ParameterDecorator;
+export function RequestParam(
+  key?: string,
+  defaultValue?: string,
+): ParameterDecorator {
   return (target, propertyKey, parameterIndex) => {
     if (propertyKey == null) {
       return;
@@ -14,13 +22,13 @@ export function RequestParam(key?: string): ParameterDecorator {
     );
 
     if (builder != null) {
-      builder.add(parameterIndex, key);
+      builder.add(parameterIndex, key, defaultValue);
       return;
     }
 
     Reflect.defineMetadata(
       REQUEST_PARAM_METADATA,
-      new RequestParamBuilder(parameterIndex, key),
+      new RequestParamBuilder(parameterIndex, key, defaultValue),
       target,
       propertyKey,
     );