Add support for different serialization strategies for query parameters

see https://swagger.io/docs/specification/v3_0/serialization/#query-parameters

packages/commons/src/core/ParameterSerializer.test.ts

@@ -0,0 +1,147 @@
+import { ParamSerializer } from "./ParameterSerializer.js";
+import {
+  QuerySerializationStyles,
+  SerializationOptions,
+} from "../types/index.js";
+
+type SerializerOptions = Record<
+  string,
+  SerializationOptions<QuerySerializationStyles>
+>;
+
+function getDecodedUrlString(serializer: ParamSerializer): string {
+  return decodeURIComponent(serializer.getSearchParams().toString());
+}
+
+describe("QueryParamSerializer", () => {
+  describe("Primitive Values", () => {
+    test.each([
+      {
+        value: "value",
+        expected: "key=value",
+      },
+      {
+        value: 123,
+        expected: "key=123",
+      },
+      {
+        value: true,
+        expected: "key=true",
+      },
+      {
+        value: false,
+        expected: "key=false",
+      },
+    ])("serializes primitive value $value", ({ value, expected }) => {
+      const options: SerializerOptions = {};
+      const serializer = new ParamSerializer(options);
+
+      serializer.serializeQueryParam("key", value);
+
+      expect(getDecodedUrlString(serializer)).toBe(expected);
+    });
+  });
+
+  describe("Array Serialization", () => {
+    test.each([
+      {
+        style: "form",
+        explode: true,
+        expected: "arrayParam=value1&arrayParam=value2",
+      },
+      {
+        style: "form",
+        explode: false,
+        expected: "arrayParam=value1,value2",
+      },
+      {
+        style: "spaceDelimited",
+        explode: false,
+        // URLSearchParams encodes spaces as plus signs (+)
+        // https://developer.mozilla.org/en-US/docs/Web/API/URLSearchParams#preserving_plus_signs
+        expected: "arrayParam=value1+value2",
+      },
+      {
+        style: "pipeDelimited",
+        explode: false,
+        expected: "arrayParam=value1|value2",
+      },
+    ] as const)(
+      "serializes arrays in $style style with explode=$explode",
+      ({ style, explode, expected }) => {
+        const options: SerializerOptions = {
+          arrayParam: { style, explode },
+        };
+        const serializer = new ParamSerializer(options);
+
+        serializer.serializeQueryParam("arrayParam", ["value1", "value2"]);
+
+        expect(getDecodedUrlString(serializer)).toBe(expected);
+      },
+    );
+
+    test("throws an error for unsupported array serialization styles", () => {
+      const options: SerializerOptions = {
+        arrayParam: { style: "deepObject" },
+      };
+      const serializer = new ParamSerializer(options);
+
+      expect(() => {
+        serializer.serializeQueryParam("arrayParam", ["value1", "value2"]);
+      }).toThrow("Unsupported serialization style for arrays: 'deepObject'");
+    });
+  });
+
+  describe("Object Serialization", () => {
+    test.each([
+      {
+        style: "form",
+        explode: true,
+        expected: "foo=bar&baz=qux",
+      },
+      {
+        style: "form",
+        explode: false,
+        expected: "objectParam=foo,bar,baz,qux",
+      },
+      {
+        style: "deepObject",
+        explode: true,
+        expected: "objectParam[foo]=bar&objectParam[baz]=qux",
+      },
+      {
+        style: "contentJSON",
+        explode: true,
+        expected: 'objectParam={"foo":"bar","baz":"qux"}',
+      },
+    ] as const)(
+      "serializes objects in $style style with explode=$explode",
+      ({ style, explode, expected }) => {
+        const options: SerializerOptions = {
+          objectParam: { style, explode },
+        };
+        const serializer = new ParamSerializer(options);
+
+        serializer.serializeQueryParam("objectParam", {
+          foo: "bar",
+          baz: "qux",
+        });
+
+        expect(getDecodedUrlString(serializer)).toBe(expected);
+      },
+    );
+
+    test("throws an error for unsupported object serialization styles", () => {
+      const options: SerializerOptions = {
+        objectParam: { style: "pipeDelimited" },
+      };
+      const serializer = new ParamSerializer(options);
+
+      expect(() => {
+        serializer.serializeQueryParam("objectParam", { foo: "bar" });
+      }).toThrow(
+        "Unsupported serialization style for objects: 'pipeDelimited'",
+      );
+    });
+  });
+});

packages/commons/src/core/ParameterSerializer.ts

@@ -0,0 +1,135 @@
+import {
+  QuerySerializationStyles,
+  SerializationOptions,
+} from "../types/index.js";
+
+type QuerySerializationOptions = SerializationOptions<QuerySerializationStyles>;
+
+export class ParamSerializer {
+  private readonly searchParams: URLSearchParams;
+  private readonly options: Record<string, QuerySerializationOptions>;
+
+  constructor(options: Record<string, QuerySerializationOptions>) {
+    this.options = options;
+    this.searchParams = new URLSearchParams();
+  }
+
+  serializeQueryParam(key: string, value: unknown): this {
+    const config = this.options[key];
+
+    switch (true) {
+      case Array.isArray(value):
+        this.handleArraySerialization(key, value, config);
+        break;
+      case typeof value === "object" && value !== null:
+        this.handleObjectSerialization(key, value, config);
+        break;
+      default:
+        this.handlePrimitiveSerialization(key, value);
+    }
+
+    return this;
+  }
+
+  getSearchParams(): URLSearchParams {
+    return this.searchParams;
+  }
+
+  private handlePrimitiveSerialization(key: string, value: unknown): void {
+    this.searchParams.append(key, String(value));
+  }
+
+  private handleArraySerialization(
+    key: string,
+    value: unknown[],
+    styleOptions: QuerySerializationOptions = { style: "form", explode: true },
+  ): void {
+    const { style, explode = true } = styleOptions;
+
+    switch (style) {
+      case "form":
+        this.serializeArrayForm(key, value, explode);
+        break;
+      case "spaceDelimited":
+        this.serializeArrayDelimited(key, value, " ");
+        break;
+      case "pipeDelimited":
+        this.serializeArrayDelimited(key, value, "|");
+        break;
+      default:
+        throw new Error(
+          `Unsupported serialization style for arrays: '${style}'`,
+        );
+    }
+  }
+
+  private serializeArrayForm(
+    key: string,
+    value: unknown[],
+    explode: boolean,
+  ): void {
+    if (explode) {
+      value.forEach((item) => this.searchParams.append(key, String(item)));
+    } else {
+      this.serializeArrayDelimited(key, value, ",");
+    }
+  }
+
+  private serializeArrayDelimited(
+    key: string,
+    value: unknown[],
+    delimiter: string,
+  ): void {
+    this.searchParams.append(key, value.join(delimiter));
+  }
+
+  private handleObjectSerialization(
+    key: string,
+    value: object,
+    styleOptions: QuerySerializationOptions = {
+      style: "deepObject",
+      explode: true,
+    },
+  ): void {
+    const { style, explode = true } = styleOptions;
+
+    switch (style) {
+      case "form":
+        this.serializeObjectForm(key, value, explode);
+        break;
+      case "deepObject":
+        this.serializeObjectDeepObject(key, value);
+        break;
+      case "contentJSON":
+        this.searchParams.append(key, JSON.stringify(value));
+        break;
+      default:
+        throw new Error(
+          `Unsupported serialization style for objects: '${style}'`,
+        );
+    }
+  }
+
+  private serializeObjectForm(
+    key: string,
+    value: object,
+    explode: boolean,
+  ): void {
+    if (explode) {
+      Object.entries(value).forEach(([k, v]) =>
+        this.searchParams.append(k, String(v)),
+      );
+    } else {
+      const serialized = Object.entries(value)
+        .map(([k, v]) => `${k},${v}`)
+        .join(",");
+      this.searchParams.append(key, serialized);
+    }
+  }
+
+  private serializeObjectDeepObject(key: string, value: object): void {
+    Object.entries(value).forEach(([k, v]) =>
+      this.searchParams.append(`${key}[${k}]`, String(v)),
+    );
+  }
+}

packages/commons/src/core/Request.test.ts

@@ -1,7 +1,7 @@
 import Request from "./Request.js";
 import { AxiosInstance } from "axios";
 import { jest } from "@jest/globals";
-import { QueryParameters } from "../types/index.js";
+import { OpenAPIOperation, QueryParameters } from "../types/index.js";
 
 const requestFn = jest.fn();
 
@@ -20,8 +20,14 @@ describe("query parameters", () => {
     method: "GET",
   } as const;
 
-  const executeRequest = (query: QueryParameters): string => {
-    const request = new Request(op, { queryParameters: query });
+  const executeRequest = (
+    query: QueryParameters,
+    opOverwrites?: Partial<OpenAPIOperation>,
+  ): string => {
+    const request = new Request(
+      { ...op, ...opOverwrites },
+      { queryParameters: query },
+    );
     request.execute(mockedAxios);
     const requestConfig = requestFn.mock.calls[0][0] as {
       params: URLSearchParams;
@@ -60,13 +66,21 @@ describe("query parameters", () => {
     expect(query).toBe("foo=bar&foo=bam");
   });
 
-  test("Number, boolean, JSON", () => {
-    const query = executeRequest({
-      foo: 1,
-      bar: true,
-      baz: { some: "value" },
-    });
+  test("Number, boolean, JSON, deepObject", () => {
+    const query = executeRequest(
+      {
+        foo: 1,
+        bar: true,
+        baz: { some: "value" },
+        deep: { object: "value" },
+      },
+      {
+        serialization: { query: { baz: { style: "contentJSON" } } },
+      },
+    );
 
-    expect(query).toBe("foo=1&bar=true&baz=%7B%22some%22%3A%22value%22%7D");
+    expect(query).toBe(
+      "foo=1&bar=true&baz=%7B%22some%22%3A%22value%22%7D&deep%5Bobject%5D=value",
+    );
   });
 });

packages/commons/src/core/Request.ts

@@ -11,6 +11,7 @@ import {
   AxiosRequestConfig,
   RawAxiosRequestHeaders,
 } from "axios";
+import { ParamSerializer } from "./ParameterSerializer.js";
 
 export class Request<TOp extends OpenAPIOperation> {
   private readonly operationDescriptor: TOp;
@@ -91,30 +92,18 @@ export class Request<TOp extends OpenAPIOperation> {
     }
 
     if (typeof query === "object") {
-      const searchParams = new URLSearchParams();
+      const serializer = new ParamSerializer(
+        this.operationDescriptor.serialization?.query ?? {},
+      );
 
       for (const [key, value] of Object.entries(query)) {
         if (value === undefined) {
           continue;
         }
-
-        if (Array.isArray(value)) {
-          for (const arrayItem of value) {
-            searchParams.append(key, arrayItem);
-          }
-        } else {
-          searchParams.append(
-            key,
-            typeof value === "string" ||
-              typeof value === "number" ||
-              typeof value === "boolean"
-              ? value.toString()
-              : JSON.stringify(value),
-          );
-        }
+        serializer.serializeQueryParam(key, value);
       }
 
-      return searchParams;
+      return serializer.getSearchParams();
     }
 
     throw new Error(`Unexpected query parameter type (${typeof query})`);