Implement writer for JSON-formatted extensions

Author: nickrolfe

extensions/ql-vscode/src/model-editor/extension-serialization.ts

@@ -400,8 +400,7 @@ export function modelExtensionFileToString(
     case ExtensionFormat.Yaml:
       return modelExtensionFileToYaml(data, headerComment);
     case ExtensionFormat.Json:
-      // TODO: implement JSON serialization
-      return "<JSON placeholder>";
+      return modelExtensionFileToJson(data, headerComment);
     default:
       assertNever(format);
   }
@@ -432,6 +431,36 @@ function modelExtensionFileToYaml(
 ${extensions.join("\n")}`;
 }
 
+function modelExtensionFileToJson(
+  data: ModelExtensionFile,
+  headerComment?: string,
+): string {
+  const extensions = data.extensions
+    .map((extension) => {
+      const data =
+        extension.data.length === 0
+          ? "[]"
+          : `[\n${extension.data
+              .map((row) => `        ${JSON.stringify(row)}`)
+              .join(",\n")}\n      ]`;
+
+      return `{
+      "addsTo": {
+        "pack": "${extension.addsTo.pack}",
+        "extensible": "${extension.addsTo.extensible}"
+      },
+      "data": ${data}
+    }`;
+    })
+    .filter((extensions) => extensions !== "");
+
+  return `${headerComment ? `// ${headerComment}\n\n` : ""}{
+  "extensions": [
+    ${extensions.join(",\n    ")}
+  ]
+}`;
+}
+
 function deserializeToObject(contents: string, filename: string) {
   const format = getFormatFromFileName(filename);
   switch (format) {

extensions/ql-vscode/test/unit-tests/model-editor/extension-serialization.test.ts

@@ -935,7 +935,40 @@ describe("createDataExtensionYamlsForApplicationMode", () => {
     data:
       - ["org.sql2o","Query","executeScalar","(Class)","summary","manual"]
 `,
-      "models/spring-boot.model.json": "<JSON placeholder>",
+      "models/spring-boot.model.json": `{
+  "extensions": [
+    {
+      "addsTo": {
+        "pack": "codeql/java-all",
+        "extensible": "sourceModel"
+      },
+      "data": []
+    },
+    {
+      "addsTo": {
+        "pack": "codeql/java-all",
+        "extensible": "sinkModel"
+      },
+      "data": []
+    },
+    {
+      "addsTo": {
+        "pack": "codeql/java-all",
+        "extensible": "summaryModel"
+      },
+      "data": []
+    },
+    {
+      "addsTo": {
+        "pack": "codeql/java-all",
+        "extensible": "neutralModel"
+      },
+      "data": [
+        ["org.springframework.boot","SpringApplication","run","(Class,String[])","summary","manual"]
+      ]
+    }
+  ]
+}`,
     });
   });
 });
@@ -1722,9 +1755,21 @@ extensions:
 `);
   });
   it("should return JSON", () => {
-    expect(
-      modelExtensionFileToString(modelExtensionFile, ExtensionFormat.Json),
-    ).toBe("<JSON placeholder>");
+    expect(modelExtensionFileToString(modelExtensionFile, ExtensionFormat.Json))
+      .toBe(`{
+  "extensions": [
+    {
+      "addsTo": {
+        "pack": "acme/super-pack",
+        "extensible": "fooModel"
+      },
+      "data": [
+        ["abc",123,true],
+        ["def",124,false]
+      ]
+    }
+  ]
+}`);
   });
   it("should return JSON with a header comment", () => {
     expect(
@@ -1733,6 +1778,21 @@ extensions:
         ExtensionFormat.Json,
         "Test header comment",
       ),
-    ).toBe("<JSON placeholder>");
+    ).toBe(`// Test header comment
+
+{
+  "extensions": [
+    {
+      "addsTo": {
+        "pack": "acme/super-pack",
+        "extensible": "fooModel"
+      },
+      "data": [
+        ["abc",123,true],
+        ["def",124,false]
+      ]
+    }
+  ]
+}`);
   });
 });