feat: represent field masks as string[]

README.markdown

@@ -620,24 +620,19 @@ Their interpretation is defined by the Protobuf specification, and libraries are
 
 `ts-proto` currently automatically converts these messages to their corresponding native types.
 
-- Wrapper Types:
-
-  * [google.protobuf.DoubleValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#DoubleValue) ⇆ `number | undefined`
-  * [google.protobuf.FloatValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#FloatValue) ⇆ `number | undefined`
-  * [google.protobuf.Int64Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#Int64Value) ⇆ `number | undefined`
-  * [google.protobuf.UInt64Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#UInt64Value) ⇆ `number | undefined`
-  * [google.protobuf.Int32Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#Int32Value) ⇆ `number | undefined`
-  * [google.protobuf.UInt32Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#UInt32Value) ⇆ `number | undefined`
-  * [google.protobuf.BoolValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#BoolValue) ⇆ `boolean | undefined`
-  * [google.protobuf.StringValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#StringValue) ⇆ `string | undefined`
-  * [google.protobuf.BytesValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#google.protobuf.BytesValue) ⇆ `Uint8Array | undefined`
-
-- JSON Types (Struct Types):
-
-  * [google.protobuf.Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#Value)  ⇆ `any | undefined` (i.e. `number | string | boolean | null | array | object`)
-  * [google.protobuf.ListValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#ListValue) ⇆ `any[]`
-  * [google.protobuf.Struct](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#Struct) ⇆ `{ [key: string]: any } | undefined`
-  * [google.protobuf.FieldMask](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#fieldmask) ⇆ `string[]` (only in the JSON, `FieldMask` is still a message)
+ * [google.protobuf.BoolValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#boolvalue) ⇆ `boolean`
+ * [google.protobuf.BytesValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#bytesvalue) ⇆ `Uint8Array`
+ * [google.protobuf.DoubleValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#doublevalue) ⇆ `number`
+ * [google.protobuf.FieldMask](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#fieldmask) ⇆ `string[]`
+ * [google.protobuf.FloatValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#floatvalue) ⇆ `number`
+ * [google.protobuf.Int32Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#int32value) ⇆ `number`
+ * [google.protobuf.Int64Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#int64value) ⇆ `number`
+ * [google.protobuf.ListValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#listvalue) ⇆ `any[]`
+ * [google.protobuf.UInt32Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#uint32value) ⇆ `number`
+ * [google.protobuf.UInt64Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#uint64value) ⇆ `number`
+ * [google.protobuf.StringValue](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#stringvalue) ⇆ `string`
+ * [google.protobuf.Value](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#value)  ⇆ `any` (i.e. `number | string | boolean | null | array | object`)
+ * [google.protobuf.Struct](https://developers.google.com/protocol-buffers/docs/reference/google.protobuf#struct) ⇆ `{ [key: string]: any }`
 
 ## Wrapper Types
 

integration/fieldmask/fieldmask-test.ts

@@ -5,23 +5,50 @@ let data = {
 };
 
 describe('fieldmask', () => {
-  it('can decode JSON', () => {
+  it('can decode canonical JSON', () => {
     const f = FieldMaskMessage.fromJSON(data);
     expect(f).toMatchInlineSnapshot(`
       Object {
-        "fieldMask": Object {
-          "paths": Array [
-            "a",
-            "b",
-            "c.d",
-          ],
-        },
+        "fieldMask": Array [
+          "a",
+          "b",
+          "c.d",
+        ],
+      }
+    `);
+  });
+
+  it('can decode non-canonical JSON', () => {
+    const f = FieldMaskMessage.fromJSON({
+      fieldMask: {
+        paths: ['a', 'b', 'c.d'],
+      }
+    });
+    expect(f).toMatchInlineSnapshot(`
+      Object {
+        "fieldMask": Array [
+          "a",
+          "b",
+          "c.d",
+        ],
       }
     `);
   });
 
   it('can encode JSON', () => {
-    const f = FieldMaskMessage.toJSON({ fieldMask: { paths: ['a', 'b', 'c.d'] } });
+    const f = FieldMaskMessage.toJSON({ fieldMask: ['a', 'b', 'c.d'] });
     expect(f).toEqual(data);
   });
+
+  it('skips empty paths', () => {
+    const f = FieldMaskMessage.fromJSON({fieldMask: 'a,,c.d'});
+    expect(f).toMatchInlineSnapshot(`
+      Object {
+        "fieldMask": Array [
+          "a",
+          "c.d",
+        ],
+      }
+    `);
+  });
 });

integration/fieldmask/fieldmask.ts

@@ -6,7 +6,7 @@ import { FieldMask } from './google/protobuf/field_mask';
 export const protobufPackage = '';
 
 export interface FieldMaskMessage {
-  fieldMask: FieldMask | undefined;
+  fieldMask: string[] | undefined;
 }
 
 function createBaseFieldMaskMessage(): FieldMaskMessage {
@@ -16,7 +16,7 @@ function createBaseFieldMaskMessage(): FieldMaskMessage {
 export const FieldMaskMessage = {
   encode(message: FieldMaskMessage, writer: Writer = Writer.create()): Writer {
     if (message.fieldMask !== undefined) {
-      FieldMask.encode(message.fieldMask, writer.uint32(10).fork()).ldelim();
+      FieldMask.encode(FieldMask.wrap(message.fieldMask), writer.uint32(10).fork()).ldelim();
     }
     return writer;
   },
@@ -29,7 +29,7 @@ export const FieldMaskMessage = {
       const tag = reader.uint32();
       switch (tag >>> 3) {
         case 1:
-          message.fieldMask = FieldMask.decode(reader, reader.uint32());
+          message.fieldMask = FieldMask.unwrap(FieldMask.decode(reader, reader.uint32()));
           break;
         default:
           reader.skipType(tag & 7);
@@ -41,20 +41,19 @@ export const FieldMaskMessage = {
 
   fromJSON(object: any): FieldMaskMessage {
     return {
-      fieldMask: isSet(object.fieldMask) ? { paths: object.fieldMask.split(',') } : undefined,
+      fieldMask: isSet(object.fieldMask) ? FieldMask.unwrap(FieldMask.fromJSON(object.fieldMask)) : undefined,
     };
   },
 
   toJSON(message: FieldMaskMessage): unknown {
     const obj: any = {};
-    message.fieldMask !== undefined && (obj.fieldMask = message.fieldMask.paths.join());
+    message.fieldMask !== undefined && (obj.fieldMask = FieldMask.toJSON(FieldMask.wrap(message.fieldMask)));
     return obj;
   },
 
   fromPartial<I extends Exact<DeepPartial<FieldMaskMessage>, I>>(object: I): FieldMaskMessage {
     const message = createBaseFieldMaskMessage();
-    message.fieldMask =
-      object.fieldMask !== undefined && object.fieldMask !== null ? FieldMask.fromPartial(object.fieldMask) : undefined;
+    message.fieldMask = object.fieldMask ?? undefined;
     return message;
   },
 };

integration/fieldmask/google/protobuf/field_mask.ts

@@ -242,25 +242,32 @@ export const FieldMask = {
 
   fromJSON(object: any): FieldMask {
     return {
-      paths: Array.isArray(object?.paths) ? object.paths.map((e: any) => String(e)) : [],
+      paths:
+        typeof object === 'string'
+          ? object.split(',').filter(Boolean)
+          : Array.isArray(object?.paths)
+          ? object.paths.map(String)
+          : [],
     };
   },
 
-  toJSON(message: FieldMask): unknown {
-    const obj: any = {};
-    if (message.paths) {
-      obj.paths = message.paths.map((e) => e);
-    } else {
-      obj.paths = [];
-    }
-    return obj;
+  toJSON(message: FieldMask): string {
+    return message.paths.join(',');
   },
 
   fromPartial<I extends Exact<DeepPartial<FieldMask>, I>>(object: I): FieldMask {
     const message = createBaseFieldMask();
     message.paths = object.paths?.map((e) => e) || [];
     return message;
   },
+
+  wrap(paths: string[]): FieldMask {
+    return { paths: paths };
+  },
+
+  unwrap(message: FieldMask): string[] {
+    return message.paths;
+  },
 };
 
 type Builtin = Date | Function | Uint8Array | string | number | boolean | undefined;

package.json

@@ -11,6 +11,7 @@
     "build": "yarn tsc",
     "build:test": "yarn proto2bin && yarn proto2pbjs && yarn bin2ts",
     "build:test:local": "yarn proto2bin:local && yarn proto2pbjs:local && yarn bin2ts:local",
+    "prepare": "yarn build",
     "proto2bin": "docker-compose run --rm protoc update-bins.sh",
     "proto2bin-node": "docker-compose run --rm node update-bins.sh",
     "proto2pbjs": "docker-compose run --rm protoc pbjs.sh",

src/main.ts

@@ -13,6 +13,7 @@ import {
   isBytesValueType,
   isEnum,
   isFieldMaskType,
+  isFieldMaskTypeName,
   isListValueType,
   isListValueTypeName,
   isLong,
@@ -164,8 +165,8 @@ export function generateFile(ctx: Context, fileDesc: FileDescriptorProto): [stri
           staticMembers.push(generateDecode(ctx, fullName, message));
         }
         if (options.outputJsonMethods) {
-          staticMembers.push(generateFromJson(ctx, fullName, message));
-          staticMembers.push(generateToJson(ctx, fullName, message));
+          staticMembers.push(generateFromJson(ctx, fullName, fullTypeName, message));
+          staticMembers.push(generateToJson(ctx, fullName, fullTypeName, message));
         }
         if (options.outputPartialMethods) {
           staticMembers.push(generateFromPartial(ctx, fullName, message));
@@ -819,7 +820,7 @@ function generateDecode(ctx: Context, fullName: string, messageDesc: DescriptorP
     } else if (isValueType(ctx, field)) {
       const type = basicTypeName(ctx, field, { keepValueType: true });
       const unwrap = (decodedValue: any): Code => {
-        if (isListValueType(field) || isStructType(field) || isAnyValueType(field)) {
+        if (isListValueType(field) || isStructType(field) || isAnyValueType(field) || isFieldMaskType(field)) {
           return code`${type}.unwrap(${decodedValue})`;
         }
         return code`${decodedValue}.value`;
@@ -944,7 +945,7 @@ function generateEncode(ctx: Context, fullName: string, messageDesc: DescriptorP
 
       const type = basicTypeName(ctx, field, { keepValueType: true });
       const wrappedValue = (place: string): Code => {
-        if (isAnyValueType(field) || isListValueType(field) || isStructType(field)) {
+        if (isAnyValueType(field) || isListValueType(field) || isStructType(field) || isFieldMaskType(field)) {
           return code`${type}.wrap(${place})`;
         }
         return code`{${maybeTypeField} value: ${place}!}`;
@@ -1094,7 +1095,7 @@ function generateEncode(ctx: Context, fullName: string, messageDesc: DescriptorP
  * This is very similar to decode, we loop through looking for properties, with
  * a few special cases for https://developers.google.com/protocol-buffers/docs/proto3#json.
  * */
-function generateFromJson(ctx: Context, fullName: string, messageDesc: DescriptorProto): Code {
+function generateFromJson(ctx: Context, fullName: string, fullTypeName: string, messageDesc: DescriptorProto): Code {
   const { options, utils, typeMap } = ctx;
   const chunks: Code[] = [];
 
@@ -1112,6 +1113,16 @@ function generateFromJson(ctx: Context, fullName: string, messageDesc: Descripto
     messageDesc.field.filter(isWithinOneOf).filter((field) => field.oneofIndex === oneofIndex)
   );
 
+  const canonicalFromJson: { [key: string]: { [field: string]: (from: string) => Code } } = {
+    ['google.protobuf.FieldMask']: {
+      paths: (from: string) => code`typeof(${from}) === 'string'
+        ? ${from}.split(",").filter(Boolean)
+        : Array.isArray(${from}?.paths)
+        ? ${from}.paths.map(String)
+        : []`,
+    },
+  };
+
   // add a check for each incoming field
   messageDesc.field.forEach((field) => {
     const fieldName = maybeSnakeToCamel(field.name, options);
@@ -1151,7 +1162,8 @@ function generateFromJson(ctx: Context, fullName: string, messageDesc: Descripto
       } else if (isAnyValueType(field) || isStructType(field)) {
         return code`${from}`;
       } else if (isFieldMaskType(field)) {
-        return code`{paths: ${from}.split(",")}`;
+        const type = basicTypeName(ctx, field, { keepValueType: true });
+        return code`${type}.unwrap(${type}.fromJSON(${from}))`;
       } else if (isListValueType(field)) {
         return code`[...${from}]`;
       } else if (isValueType(ctx, field)) {
@@ -1210,7 +1222,9 @@ function generateFromJson(ctx: Context, fullName: string, messageDesc: Descripto
     };
 
     // and then use the snippet to handle repeated fields if necessary
-    if (isRepeated(field)) {
+    if (canonicalFromJson[fullTypeName]?.[fieldName]) {
+      chunks.push(code`${fieldName}: ${canonicalFromJson[fullTypeName][fieldName]('object')},`);
+    } else if (isRepeated(field)) {
       if (isMapType(ctx, messageDesc, field)) {
         const fieldType = toTypeName(ctx, messageDesc, field);
         const i = maybeCastToNumber(ctx, messageDesc, field, 'key');
@@ -1282,10 +1296,32 @@ function generateFromJson(ctx: Context, fullName: string, messageDesc: Descripto
   return joinCode(chunks, { on: '\n' });
 }
 
-function generateToJson(ctx: Context, fullName: string, messageDesc: DescriptorProto): Code {
+function generateCanonicalToJson(fullName: string, fullProtobufTypeName: string): Code | undefined {
+  if (isFieldMaskTypeName(fullProtobufTypeName)) {
+    return code`
+    toJSON(message: ${fullName}): string {
+      return message.paths.join(',');
+    }
+  `;
+  }
+  return undefined;
+}
+
+function generateToJson(
+  ctx: Context,
+  fullName: string,
+  fullProtobufTypeName: string,
+  messageDesc: DescriptorProto
+): Code {
   const { options, utils, typeMap } = ctx;
   const chunks: Code[] = [];
 
+  const canonicalToJson = generateCanonicalToJson(fullName, fullProtobufTypeName);
+  if (canonicalToJson) {
+    chunks.push(canonicalToJson);
+    return joinCode(chunks, { on: '\n' });
+  }
+
   // create the basic function declaration
   chunks.push(code`
     toJSON(${messageDesc.field.length > 0 ? 'message' : '_'}: ${fullName}): unknown {
@@ -1343,7 +1379,8 @@ function generateToJson(ctx: Context, fullName: string, messageDesc: DescriptorP
       } else if (isAnyValueType(field)) {
         return code`${from}`;
       } else if (isFieldMaskType(field)) {
-        return code`${from}.paths.join()`;
+        const type = basicTypeName(ctx, field, { keepValueType: true });
+        return code`${type}.toJSON(${type}.wrap(${from}))`;
       } else if (isMessage(field) && !isValueType(ctx, field) && !isMapType(ctx, messageDesc, field)) {
         const type = basicTypeName(ctx, field, { keepValueType: true });
         return code`${from} ? ${type}.toJSON(${from}) : ${defaultValue(ctx, field)}`;
@@ -1598,6 +1635,12 @@ function generateWrap(ctx: Context, fullProtoTypeName: string): Code[] {
     }`);
   }
 
+  if (isFieldMaskTypeName(fullProtoTypeName)) {
+    chunks.push(code`wrap(paths: string[]): FieldMask {
+      return {paths: paths};
+    }`);
+  }
+
   return chunks;
 }
 
@@ -1658,6 +1701,12 @@ function generateUnwrap(ctx: Context, fullProtoTypeName: string): Code[] {
     }`);
   }
 
+  if (isFieldMaskTypeName(fullProtoTypeName)) {
+    chunks.push(code`unwrap(message: FieldMask): string[] {
+      return message.paths;
+    }`);
+  }
+
   return chunks;
 }
 

src/types.ts

@@ -484,6 +484,8 @@ export function valueTypeName(ctx: Context, typeName: string): Code | undefined
       return code`any`;
     case '.google.protobuf.Struct':
       return code`{[key: string]: any}`;
+    case '.google.protobuf.FieldMask':
+      return code`string[]`;
     default:
       return undefined;
   }