[api] Add hasTrailingComma getter in the RemoteNodeList class

packages/typescript/src/api/node/encoder.ts

@@ -267,7 +267,7 @@ export function encodeNode(node: Node): Uint8Array {
             0, // next
             parentIndex,
             list.length, // data for NodeList is its length
-            0, // flags
+            list.hasTrailingComma ? 1 : 0, // NodeLists have no AST flags; this slot is reused for hasTrailingComma
         );
 
         const saveParentIndex = parentIndex;

packages/typescript/src/api/node/node.generated.ts

@@ -43,7 +43,6 @@ export class RemoteNodeList extends Array<RemoteNode> implements NodeArray<Remot
     }
 
     parent: RemoteNode;
-    hasTrailingComma?: boolean;
     transformFlags: number = 0;
     protected view: DataView;
     protected index: number;
@@ -71,6 +70,10 @@ export class RemoteNodeList extends Array<RemoteNode> implements NodeArray<Remot
         return this.view.getUint32(this._byteIndex + NODE_OFFSET_DATA, true);
     }
 
+    get hasTrailingComma(): boolean {
+        return (this.view.getUint32(this._byteIndex + NODE_OFFSET_FLAGS, true) & 1) !== 0;
+    }
+
     private sourceFile: SourceFileInfo;
 
     constructor(view: DataView, index: number, parent: RemoteNode, sourceFile: SourceFileInfo, offsetNodes: number) {

packages/typescript/src/api/node/protocol.ts

@@ -1,4 +1,4 @@
-export const PROTOCOL_VERSION = 7;
+export const PROTOCOL_VERSION = 8;
 
 export const HEADER_OFFSET_METADATA = 0;
 export const HEADER_OFFSET_HASH_LO0 = 4;

packages/typescript/test/async/api.test.ts

@@ -7,6 +7,7 @@ import {
     getSynthesizedDeepClone,
     InternalSymbolName,
     isCallExpression,
+    isExpressionStatement,
     isFunctionDeclaration,
     isIdentifier,
     isImportDeclaration,
@@ -1236,6 +1237,29 @@ describe("SourceFile", () => {
     });
 });
 
+describe("NodeArray", () => {
+    test("hasTrailingComma", async () => {
+        const api = spawnAPI({
+            "/tsconfig.json": JSON.stringify({ compilerOptions: { strict: true } }),
+            "/src/main.ts": `declare function foo(...args: any): void;\nfoo("a", "b",);\nfoo("a", "b");`,
+        });
+        try {
+            const snapshot = await api.updateSnapshot({ openProject: "/tsconfig.json" });
+            const project = snapshot.getProject("/tsconfig.json")!;
+            const sourceFile = await project.program.getSourceFile("/src/main.ts");
+            assert.ok(sourceFile);
+            const statements = sourceFile.statements.filter(isExpressionStatement);
+            assert.ok(isCallExpression(statements[0].expression));
+            assert.equal(statements[0].expression.arguments.hasTrailingComma, true);
+            assert.ok(isCallExpression(statements[1].expression));
+            assert.equal(statements[1].expression.arguments.hasTrailingComma, false);
+        }
+        finally {
+            await api.close();
+        }
+    });
+});
+
 test("unicode escapes", async () => {
     const api = spawnAPI({
         "/tsconfig.json": "{}",

packages/typescript/test/encoder.test.ts

@@ -67,7 +67,7 @@ describe("Encoder", () => {
         // Verify header
         const view = new DataView(encoded.buffer, encoded.byteOffset, encoded.byteLength);
         const metadata = view.getUint32(0, true);
-        assert.strictEqual(metadata >>> 24, 7, "protocol version should be 7");
+        assert.strictEqual(metadata >>> 24, 8, "protocol version should be 8");
 
         // Verify we can decode it
         const decoded = decode(encoded);
@@ -179,11 +179,11 @@ describe("Encoder", () => {
         assert.strictEqual(rootKind, SyntaxKind.IfStatement);
     });
 
-    test("protocol version is 7", () => {
+    test("protocol version is 8", () => {
         const sf = makeSF("", "/test.ts", []);
         const encoded = encodeSourceFile(sf);
         const view = new DataView(encoded.buffer, encoded.byteOffset, encoded.byteLength);
-        assert.strictEqual(view.getUint32(0, true) >>> 24, 7);
+        assert.strictEqual(view.getUint32(0, true) >>> 24, 8);
     });
 
     test("encodes source files without content mapping metadata", () => {

packages/typescript/test/sync/api.test.ts

@@ -15,6 +15,7 @@ import {
     getSynthesizedDeepClone,
     InternalSymbolName,
     isCallExpression,
+    isExpressionStatement,
     isFunctionDeclaration,
     isIdentifier,
     isImportDeclaration,
@@ -1152,6 +1153,29 @@ describe("SourceFile", () => {
     });
 });
 
+describe("NodeArray", () => {
+    test("hasTrailingComma", () => {
+        const api = spawnAPI({
+            "/tsconfig.json": JSON.stringify({ compilerOptions: { strict: true } }),
+            "/src/main.ts": `declare function foo(...args: any): void;\nfoo("a", "b",);\nfoo("a", "b");`,
+        });
+        try {
+            const snapshot = api.updateSnapshot({ openProject: "/tsconfig.json" });
+            const project = snapshot.getProject("/tsconfig.json")!;
+            const sourceFile = project.program.getSourceFile("/src/main.ts");
+            assert.ok(sourceFile);
+            const statements = sourceFile.statements.filter(isExpressionStatement);
+            assert.ok(isCallExpression(statements[0].expression));
+            assert.equal(statements[0].expression.arguments.hasTrailingComma, true);
+            assert.ok(isCallExpression(statements[1].expression));
+            assert.equal(statements[1].expression.arguments.hasTrailingComma, false);
+        }
+        finally {
+            api.close();
+        }
+    });
+});
+
 test("unicode escapes", () => {
     const api = spawnAPI({
         "/tsconfig.json": "{}",

tools/scripts/tsc/generate-encoder.ts

@@ -1518,7 +1518,6 @@ function emitRemoteNodeList(w: CodeWriter) {
     w.write(`    }`);
     w.write(``);
     w.write(`    parent: RemoteNode;`);
-    w.write(`    hasTrailingComma?: boolean;`);
     w.write(`    transformFlags: number = 0;`);
     w.write(`    protected view: DataView;`);
     w.write(`    protected index: number;`);
@@ -1546,6 +1545,10 @@ function emitRemoteNodeList(w: CodeWriter) {
     w.write(`        return this.view.getUint32(this._byteIndex + NODE_OFFSET_DATA, true);`);
     w.write(`    }`);
     w.write(``);
+    w.write(`    get hasTrailingComma(): boolean {`);
+    w.write(`        return (this.view.getUint32(this._byteIndex + NODE_OFFSET_FLAGS, true) & 1) !== 0;`);
+    w.write(`    }`);
+    w.write(``);
     w.write(`    private sourceFile: SourceFileInfo;`);
     w.write(``);
     w.write(`    constructor(view: DataView, index: number, parent: RemoteNode, sourceFile: SourceFileInfo, offsetNodes: number) {`);

tsc/internal/api/encoder/encoder.go

@@ -63,7 +63,7 @@ const (
 )
 
 const (
-	ProtocolVersion uint8 = 7
+	ProtocolVersion uint8 = 8
 )
 
 // Source File Binary Format
@@ -202,7 +202,8 @@ const (
 // NodeLists are represented as normal nodes with the special `kind` value `0xff_ff_ff_ff`. They are considered the parent
 // of their contents in the encoded format. A client reconstructing an AST similar to TypeScript's internal representation
 // should instead set the `parent` pointers of a NodeList's children to the NodeList's parent. A NodeList's `data` field
-// is the uint32 length of the list, and does not use one of the data types described below.
+// is the uint32 length of the list, and does not use one of the data types described below. A NodeList's `flags` field
+// is not used for AST node flags (NodeLists have none); bit 0 instead encodes `HasTrailingComma`.
 //
 // For node types other than NodeList, the node data field encodes one of the following, determined by the first 2 bits of
 // the field:
@@ -502,7 +503,7 @@ func encodeTree(rootNode *ast.Node, sourceFile *ast.SourceFile) ([]byte, *NodeIn
 					nodes[prevIndex*NodeSize+NodeOffsetNext+3] = b3
 				}
 
-				nodes = appendUint32s(nodes, SyntaxKindNodeList, utf16(nodeList.Pos()), utf16(nodeList.End()), 0, parentIndex, uint32(len(nodeList.Nodes)), 0)
+				nodes = appendUint32s(nodes, SyntaxKindNodeList, utf16(nodeList.Pos()), utf16(nodeList.End()), 0, parentIndex, uint32(len(nodeList.Nodes)), uint32(boolToByte(nodeList.HasTrailingComma())))
 
 				saveParentIndex := parentIndex
 

tsc/internal/api/encoder/encoder_test.go

@@ -37,8 +37,8 @@ func TestEncodeSourceFile(t *testing.T) {
 
 func TestEncodeContentMapperSourceFileMetadata(t *testing.T) {
 	t.Parallel()
-	if encoder.ProtocolVersion != 7 {
-		t.Fatalf("protocol version = %d, want 7", encoder.ProtocolVersion)
+	if encoder.ProtocolVersion != 8 {
+		t.Fatalf("protocol version = %d, want 8", encoder.ProtocolVersion)
 	}
 	sourceFile := parser.ParseSourceFile(ast.SourceFileParseOptions{
 		FileName: "/component.vue",