refactor: extract pure logic

Extract pure function for parsing manifest

src/io/project-manifest-io.ts

@@ -1,11 +1,9 @@
-import { AnyJson } from "@iarna/toml";
 import path from "path";
 import { CustomError } from "ts-custom-error";
 import { z } from "zod";
 import { UnityProjectManifest } from "../domain/project-manifest";
 import { DebugLog, npmDebugLog } from "../logging";
 import { assertIsError } from "../utils/error-type-guards";
-import { isZod } from "../utils/zod-utils";
 import {
   readTextFile,
   ReadTextFile,
@@ -40,7 +38,18 @@ export type LoadProjectManifest = (
 ) => Promise<UnityProjectManifest>;
 
 // TODO: Add a better schema
-const projectManifestSchema = z.object({});
+const projectManifestSchema = z.object({}).passthrough();
+
+/**
+ * Parses the content of a `manifest.json` file to a {@link UnityProjectManifest}.
+ * @param content The files content.
+ * @returns The parsed file.
+ * @throws {Error} If parsing failed.
+ */
+export function parseProjectManifest(content: string): UnityProjectManifest {
+  const json = JSON.parse(content);
+  return projectManifestSchema.parse(json) as UnityProjectManifest;
+}
 
 /**
  * Makes a {@link LoadProjectManifest} function which reads the content
@@ -56,18 +65,13 @@ export function ReadProjectManifestFile(
     const content = await readFile(manifestPath, true);
     if (content === null) throw new ManifestMissingError(manifestPath);
 
-    let json: AnyJson;
     try {
-      json = await JSON.parse(content);
+      return parseProjectManifest(content);
     } catch (error) {
       assertIsError(error);
       debugLog("Manifest parse failed because of invalid json content.", error);
       throw new ManifestMalformedError();
     }
-
-    if (!isZod(json, projectManifestSchema)) throw new ManifestMalformedError();
-
-    return json as unknown as UnityProjectManifest;
   };
 }
 

test/io/project-manifest-io.test.ts

@@ -1,26 +1,47 @@
+import path from "path";
+import { UnityProjectManifest } from "../../src/domain/project-manifest";
 import {
-  ReadProjectManifestFile,
-  WriteProjectManifestFile,
   ManifestMalformedError,
   ManifestMissingError,
   manifestPathFor,
+  parseProjectManifest,
+  ReadProjectManifestFile,
   serializeProjectManifest,
 } from "../../src/io/project-manifest-io";
-import {
-  mapScopedRegistry,
-  UnityProjectManifest,
-} from "../../src/domain/project-manifest";
-import path from "path";
-import { ReadTextFile, WriteTextFile } from "../../src/io/text-file-io";
-import { buildProjectManifest } from "../domain/data-project-manifest";
-import { DomainName } from "../../src/domain/domain-name";
-import { removeScope } from "../../src/domain/scoped-registry";
+import { ReadTextFile } from "../../src/io/text-file-io";
+import { noopLogger } from "../../src/logging";
 import { exampleRegistryUrl } from "../domain/data-registry";
 import { mockService } from "../services/service.mock";
-import { noopLogger } from "../../src/logging";
 
 const exampleProjectPath = "/some/path";
 describe("project-manifest io", () => {
+  describe("parse", () => {
+    it("should parse valid manifest", () => {
+      const content = `{ "dependencies": { "com.package.a": "1.0.0"} }`;
+
+      const parsed = parseProjectManifest(content);
+
+      expect(parsed).toEqual({
+        dependencies: {
+          "com.package.a": "1.0.0",
+        },
+      });
+    });
+
+    it("should fail for bad json", () => {
+      const content = "not : valid // json";
+
+      expect(() => parseProjectManifest(content)).toThrow(Error);
+    });
+
+    it("should fail incorrect json shape", () => {
+      // Valid json but not what we want
+      const content = `123`;
+
+      expect(() => parseProjectManifest(content)).toThrow(Error);
+    });
+  });
+
   describe("path", () => {
     it("should determine correct manifest path", () => {
       const manifestPath = manifestPathFor("test-openupm-cli");
@@ -53,7 +74,7 @@ describe("project-manifest io", () => {
       ).rejects.toBeInstanceOf(ManifestMissingError);
     });
 
-    it("should fail if manifest contains invalid json", async () => {
+    it("should fail if manifest could not be parsed", async () => {
       const { readProjectManifestFile, readFile } = makeDependencies();
       readFile.mockResolvedValue("not {} valid : json");
 
@@ -62,15 +83,6 @@ describe("project-manifest io", () => {
       ).rejects.toBeInstanceOf(ManifestMalformedError);
     });
 
-    it("should fail if manifest contains invalid content", async () => {
-      const { readProjectManifestFile, readFile } = makeDependencies();
-      readFile.mockResolvedValue(`123`);
-
-      await expect(
-        readProjectManifestFile(exampleProjectPath)
-      ).rejects.toBeInstanceOf(ManifestMalformedError);
-    });
-
     it("should load valid manifest", async () => {
       const { readProjectManifestFile, readFile } = makeDependencies();
       readFile.mockResolvedValue(