# All files / api user_data_converter.ts

95.51% Statements 234/245
89.47% Branches 102/114
100% Functions 38/38
95.36% Lines 226/237

    1
    2
    3
    4
    5
    6
    7
    8
    9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74
    75
    76
    77
    78
    79
    80
    81
    82
    83
    84
    85
    86
    87
    88
    89
    90
    91
    92
    93
    94
    95
    96
    97
    98
    99
    100
    101
    102
    103
    104
    105
    106
    107
    108
    109
    110
    111
    112
    113
    114
    115
    116
    117
    118
    119
    120
    121
    122
    123
    124
    125
    126
    127
    128
    129
    130
    131
    132
    133
    134
    135
    136
    137
    138
    139
    140
    141
    142
    143
    144
    145
    146
    147
    148
    149
    150
    151
    152
    153
    154
    155
    156
    157
    158
    159
    160
    161
    162
    163
    164
    165
    166
    167
    168
    169
    170
    171
    172
    173
    174
    175
    176
    177
    178
    179
    180
    181
    182
    183
    184
    185
    186
    187
    188
    189
    190
    191
    192
    193
    194
    195
    196
    197
    198
    199
    200
    201
    202
    203
    204
    205
    206
    207
    208
    209
    210
    211
    212
    213
    214
    215
    216
    217
    218
    219
    220
    221
    222
    223
    224
    225
    226
    227
    228
    229
    230
    231
    232
    233
    234
    235
    236
    237
    238
    239
    240
    241
    242
    243
    244
    245
    246
    247
    248
    249
    250
    251
    252
    253
    254
    255
    256
    257
    258
    259
    260
    261
    262
    263
    264
    265
    266
    267
    268
    269
    270
    271
    272
    273
    274
    275
    276
    277
    278
    279
    280
    281
    282
    283
    284
    285
    286
    287
    288
    289
    290
    291
    292
    293
    294
    295
    296
    297
    298
    299
    300
    301
    302
    303
    304
    305
    306
    307
    308
    309
    310
    311
    312
    313
    314
    315
    316
    317
    318
    319
    320
    321
    322
    323
    324
    325
    326
    327
    328
    329
    330
    331
    332
    333
    334
    335
    336
    337
    338
    339
    340
    341
    342
    343
    344
    345
    346
    347
    348
    349
    350
    351
    352
    353
    354
    355
    356
    357
    358
    359
    360
    361
    362
    363
    364
    365
    366
    367
    368
    369
    370
    371
    372
    373
    374
    375
    376
    377
    378
    379
    380
    381
    382
    383
    384
    385
    386
    387
    388
    389
    390
    391
    392
    393
    394
    395
    396
    397
    398
    399
    400
    401
    402
    403
    404
    405
    406
    407
    408
    409
    410
    411
    412
    413
    414
    415
    416
    417
    418
    419
    420
    421
    422
    423
    424
    425
    426
    427
    428
    429
    430
    431
    432
    433
    434
    435
    436
    437
    438
    439
    440
    441
    442
    443
    444
    445
    446
    447
    448
    449
    450
    451
    452
    453
    454
    455
    456
    457
    458
    459
    460
    461
    462
    463
    464
    465
    466
    467
    468
    469
    470
    471
    472
    473
    474
    475
    476
    477
    478
    479
    480
    481
    482
    483
    484
    485
    486
    487
    488
    489
    490
    491
    492
    493
    494
    495
    496
    497
    498
    499
    500
    501
    502
    503
    504
    505
    506
    507
    508
    509
    510
    511
    512
    513
    514
    515
    516
    517
    518
    519
    520
    521
    522
    523
    524
    525
    526
    527
    528
    529
    530
    531
    532
    533
    534
    535
    536
    537
    538
    539
    540
    541
    542
    543
    544
    545
    546
    547
    548
    549
    550
    551
    552
    553
    554
    555
    556
    557
    558
    559
    560
    561
    562
    563
    564
    565
    566
    567
    568
    569
    570
    571
    572
    573
    574
    575
    576
    577
    578
    579
    580
    581
    582
    583
    584
    585
    586
    587
    588
    589
    590
    591
    592
    593
    594
    595
    596
    597
    598
    599
    600
    601
    602
    603
    604
    605
    606
    607
    608
    609
    610
    611
    612
    613
    614
    615
    616
    617
    618
    619
    620
    621
    622
    623
    624
    625
    626
    627
    628
    629
    630
    631
    632
    633
    634
    635
    636
    637
    638
    639
    640
    641
    642
    643
    644
    645
    646
    647
    648
    649
    650
    651
    652
    653
    654
    655
    656
    657
    658
    659
    660
    661
    662
    663
    664
    665
    666
    667
    668
    669
    670
    671
    672
    673
    674
    675
    676
    677
    678
    679
    680
    681
    682
    683
    684
    685
    686
    687
    688

    2x

    2x
    2x

    2x

    2x
    2x
    2x
    2x
    2x
    2x

    2x
    2x

    2x
    2x

    2x

    2x

    2x

    2x

    480x
    480x
    480x

    2x
    480x
    480x
    14x

    466x

    480x
    12x

    480x

    2x

    2x

    112x
    112x
    112x

    2x
    72x

    72x
    36x

    72x

    2x

    2x
    2x
    2x
    2x
    2x

    6900x

    1392x

    5508x

    2x

    13528x
    13528x
    13528x
    13528x

    13528x
    6647x

    13528x
    13528x
    13528x

    2x
    6530x
    6530x

    6530x
    6506x

    2x
    243x
    243x

    243x
    219x

    2x

    108x

    2x

    262x

    262x

    2x

    6890x

    6890x
    278x

    2x
    6808x
    48x

    2x

    2x
    22x
    2x

    2x
    457x

    2x
    592x

    592x

    544x

    466x

    2x
    14x

    14x

    14x
    14x
    14x

    286x
    286x

    286x

    240x
    240x
    240x
    271x

    211x
    187x
    181x

    5x

    176x
    116x
    90x
    90x

    90x
    90x

    2x

    22x

    22x
    22x

    22x

    22x
    10x

    10x

    22x
    22x

    22x
    32x
    32x
    32x
    32x

    32x
    32x
    22x
    22x

    22x
    22x

    2x
    5733x

    5733x
    5733x
    5733x

    5733x

    2x
    13332x
    13332x

    12x
    12x

    2x
    13113x
    13107x
    6195x
    6159x

    6912x
    6816x

    6912x

    84x
    12x

    72x
    6828x

    92x
    80x

    6736x

    2x
    72x
    72x
    108x
    108x

    72x

    72x
    72x

    36x

    6159x
    6159x
    6159x
    6530x

    6410x
    6366x

    6039x

    2x

    6736x
    20x
    6716x
    4848x
    1345x

    3503x

    1868x
    134x
    1734x
    1572x
    162x
    18x
    144x

    48x

    96x
    17x
    79x
    9x
    70x
    22x

    48x

    2x

    92x

    92x

    92x
    16x

    12x
    6x

    6x

    6x

    76x
    76x

    2x

    20194x

    7087x
    130x
    130x

    130x

    2x

    342x
    58x
    284x
    284x

    555x
    555x

    120x
    120x

    132x

     /**
     * Copyright 2017 Google Inc.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */

    import { Timestamp } from '../api/timestamp';
    import { DatabaseId } from '../core/database_info';
    import { DocumentKey } from '../model/document_key';
    import { FieldValue, ObjectValue } from '../model/field_value';
    import {
      ArrayValue,
      BlobValue,
      BooleanValue,
      DoubleValue,
      GeoPointValue,
      IntegerValue,
      NullValue,
      RefValue,
      StringValue,
      TimestampValue
    } from '../model/field_value';
    import {
      FieldMask,
      FieldTransform,
      Mutation,
      PatchMutation,
      Precondition,
      ServerTimestampTransform,
      SetMutation,
      TransformMutation
    } from '../model/mutation';
    import { FieldPath } from '../model/path';
    import { assert, fail } from '../util/assert';
    import { Code, FirestoreError } from '../util/error';
    import { isPlainObject, valueDescription } from '../util/input_validation';
    import { AnyJs, primitiveComparator } from '../util/misc';
    import * as objUtils from '../util/obj';
    import { Dict } from '../util/obj';
    import { SortedMap } from '../util/sorted_map';
    import * as typeUtils from '../util/types';

    import { Blob } from './blob';
    import {
      FieldPath as ExternalFieldPath,
      fromDotSeparatedString
    } from './field_path';
    import {
      DeleteFieldValueImpl,
      FieldValueImpl,
      ServerTimestampFieldValueImpl
    } from './field_value';
    import { GeoPoint } from './geo_point';

    const RESERVED_FIELD_REGEX = /^__.*__$/;

    /** The result of parsing document data (e.g. for a setData call). */
    export class ParsedSetData {
      constructor(
        readonly data: ObjectValue,
        readonly fieldMask: FieldMask | null,
        readonly fieldTransforms: FieldTransform[]
      ) {}

      toMutations(key: DocumentKey, precondition: Precondition): Mutation[] {
        const mutations = [] as Mutation[];
        if (this.fieldMask !== null) {
          mutations.push(
            new PatchMutation(key, this.data, this.fieldMask, precondition)
          );
        } else {
          mutations.push(new SetMutation(key, this.data, precondition));
        }
        if (this.fieldTransforms.length > 0) {
          mutations.push(new TransformMutation(key, this.fieldTransforms));
        }
        return mutations;
      }
    }

    /** The result of parsing "update" data (i.e. for an updateData call). */
    export class ParsedUpdateData {
      constructor(
        readonly data: ObjectValue,
        readonly fieldMask: FieldMask,
        readonly fieldTransforms: FieldTransform[]
      ) {}

      toMutations(key: DocumentKey, precondition: Precondition): Mutation[] {
        const mutations = [
          new PatchMutation(key, this.data, this.fieldMask, precondition)
        ] as Mutation[];
        if (this.fieldTransforms.length > 0) {
          mutations.push(new TransformMutation(key, this.fieldTransforms));
        }
        return mutations;
      }
    }

    /*
     * Represents what type of API method provided the data being parsed; useful
     * for determining which error conditions apply during parsing and providing
     * better error messages.
     */
    enum UserDataSource {
      Set,
      Update,
      MergeSet,
      QueryValue // from a where clause or cursor bound
    }

    function isWrite(dataSource: UserDataSource) {
      switch (dataSource) {
        case UserDataSource.Set: // fall through
        case UserDataSource.MergeSet: // fall through
        case UserDataSource.Update:
          return true;
        case UserDataSource.QueryValue:
          return false;
        default:
          throw fail(`Unexpected case for UserDataSource: ${dataSource}`);
      }
    }

    /** A "context" object passed around while parsing user data. */
    class ParseContext {
      readonly fieldTransforms: FieldTransform[];
      readonly fieldMask: FieldPath[];
      /**
       * Initializes a ParseContext with the given source and path.
       *
       * @param dataSource Indicates what kind of API method this data came from.
       * @param methodName The name of the method the user called to create this
       *     ParseContext.
       * @param path A path within the object being parsed. This could be an empty
       *     path (in which case the context represents the root of the data being
       *     parsed), or a nonempty path (indicating the context represents a nested
       *     location within the data).
       * @param arrayElement Whether or not this context corresponds to an element
       *     of an array.
       * @param fieldTransforms A mutable list of field transforms encountered while
       *     parsing the data.
       * @param fieldMask A mutable list of field paths encountered while parsing
       *     the data.
       *
       * TODO(b/34871131): We don't support array paths right now, so path can be
       * null to indicate the context represents any location within an array (in
       * which case certain features will not work and errors will be somewhat
       * compromised).
       */
      constructor(
        readonly dataSource: UserDataSource,
        readonly methodName: string,
        readonly path: FieldPath | null,
        readonly arrayElement?: boolean,
        fieldTransforms?: FieldTransform[],
        fieldMask?: FieldPath[]
      ) {
        // Minor hack: If fieldTransforms is undefined, we assume this is an
        // external call and we need to validate the entire path.
        if (fieldTransforms === undefined) {
          this.validatePath();
        }
        this.arrayElement = arrayElement !== undefined ? arrayElement : false;
        this.fieldTransforms = fieldTransforms || [];
        this.fieldMask = fieldMask || [];
      }

      childContextForField(field: string): ParseContext {
        const childPath = this.path == null ? null : this.path.child(field);
        const context = new ParseContext(
          this.dataSource,
          this.methodName,
          childPath,
          /*arrayElement=*/ false,
          this.fieldTransforms,
          this.fieldMask
        );
        context.validatePathSegment(field);
        return context;
      }

      childContextForFieldPath(field: FieldPath): ParseContext {
        const childPath = this.path == null ? null : this.path.child(field);
        const context = new ParseContext(
          this.dataSource,
          this.methodName,
          childPath,
          /*arrayElement=*/ false,
          this.fieldTransforms,
          this.fieldMask
        );
        context.validatePath();
        return context;
      }

      childContextForArray(index: number): ParseContext {
        // TODO(b/34871131): We don't support array paths right now; so make path
        // null.
        return new ParseContext(
          this.dataSource,
          this.methodName,
          /*path=*/ null,
          /*arrayElement=*/ true,
          this.fieldTransforms,
          this.fieldMask
        );
      }

      createError(reason: string): Error {
        const fieldDescription =
          this.path === null || this.path.isEmpty()
            ? ''
            : ` (found in field ${this.path.toString()})`;
        return new FirestoreError(
          Code.INVALID_ARGUMENT,
          `Function ${this.methodName}() called with invalid data. ` +
            reason +
            fieldDescription
        );
      }

      private validatePath() {
        // TODO(b/34871131): Remove null check once we have proper paths for fields
        // within arrays.
        Iif (this.path === null) {
          return;
        }
        for (let i = 0; i < this.path.length; i++) {
          this.validatePathSegment(this.path.get(i));
        }
      }

      private validatePathSegment(segment: string) {
        if (isWrite(this.dataSource) && RESERVED_FIELD_REGEX.test(segment)) {
          throw this.createError('Document fields cannot begin and end with __');
        }
      }
    }
    /**
     * An interface that allows arbitrary pre-converting of user data. This
     * abstraction allows for, e.g.:
     *  * The public API to convert DocumentReference objects to DocRef objects,
     *    avoiding a circular dependency between user_data_converter.ts and
     *    database.ts
     *  * Tests to convert test-only sentinels (e.g. '<DELETE>') into types
     *    compatible with UserDataConverter.
     *
     * Returns the converted value (can return back the input to act as a no-op).
     *
     * It can also throw an Error which will be wrapped into a friendly message.
     */
    export type DataPreConverter = (input: AnyJs) => AnyJs;

    /**
     * A placeholder object for DocumentReferences in this file, in order to
     * avoid a circular dependency. See the comments for `DataPreConverter` for
     * the full context.
     */
    export class DocumentKeyReference {
      constructor(public databaseId: DatabaseId, public key: DocumentKey) {}
    }

    /**
     * Helper for parsing raw user input (provided via the API) into internal model
     * classes.
     */
    export class UserDataConverter {
      constructor(private preConverter: DataPreConverter) {}

      /** Parse document data from a non-merge set() call. */
      parseSetData(methodName: string, input: AnyJs): ParsedSetData {
        const context = new ParseContext(
          UserDataSource.Set,
          methodName,
          FieldPath.EMPTY_PATH
        );
        validatePlainObject('Data must be an object, but it was:', context, input);

        const updateData = this.parseData(input, context);

        return new ParsedSetData(
          updateData as ObjectValue,
          /* fieldMask= */ null,
          context.fieldTransforms
        );
      }

      /** Parse document data from a set() call with '{merge:true}'. */
      parseMergeData(methodName: string, input: AnyJs): ParsedSetData {
        const context = new ParseContext(
          UserDataSource.MergeSet,
          methodName,
          FieldPath.EMPTY_PATH
        );
        validatePlainObject('Data must be an object, but it was:', context, input);

        const updateData = this.parseData(input, context);
        const fieldMask = new FieldMask(context.fieldMask);
        return new ParsedSetData(
          updateData as ObjectValue,
          fieldMask,
          context.fieldTransforms
        );
      }

      /** Parse update data from an update() call. */
      parseUpdateData(methodName: string, input: AnyJs): ParsedUpdateData {
        const context = new ParseContext(
          UserDataSource.Update,
          methodName,
          FieldPath.EMPTY_PATH
        );
        validatePlainObject('Data must be an object, but it was:', context, input);

        const fieldMaskPaths = [] as FieldPath[];
        let updateData = ObjectValue.EMPTY;
        objUtils.forEach(input as Dict<AnyJs>, (key, value) => {
          const path = fieldPathFromDotSeparatedString(methodName, key);

          const childContext = context.childContextForFieldPath(path);
          value = this.runPreConverter(value, childContext);
          if (value instanceof DeleteFieldValueImpl) {
            // Add it to the field mask, but don't add anything to updateData.
            fieldMaskPaths.push(path);
          } else {
            const parsedValue = this.parseData(value, childContext);
            if (parsedValue != null) {
              fieldMaskPaths.push(path);
              updateData = updateData.set(path, parsedValue);
            }
          }
        });

        const mask = new FieldMask(fieldMaskPaths);
        return new ParsedUpdateData(updateData, mask, context.fieldTransforms);
      }

      /** Parse update data from a list of field/value arguments. */
      parseUpdateVarargs(
        methodName: string,
        field: string | ExternalFieldPath,
        value: AnyJs,
        moreFieldsAndValues: AnyJs[]
      ): ParsedUpdateData {
        const context = new ParseContext(
          UserDataSource.Update,
          methodName,
          FieldPath.EMPTY_PATH
        );
        const keys = [fieldPathFromArgument(methodName, field)];
        const values = [value];

        Iif (moreFieldsAndValues.length % 2 !== 0) {
          throw new FirestoreError(
            Code.INVALID_ARGUMENT,
            `Function ${methodName}() needs to be called with an even number ` +
              'of arguments that alternate between field names and values.'
          );
        }

        for (let i = 0; i < moreFieldsAndValues.length; i += 2) {
          keys.push(
            fieldPathFromArgument(methodName, moreFieldsAndValues[i] as
              | string
              | ExternalFieldPath)
          );
          values.push(moreFieldsAndValues[i + 1]);
        }

        const fieldMaskPaths = [] as FieldPath[];
        let updateData = ObjectValue.EMPTY;

        for (let i = 0; i < keys.length; ++i) {
          const path = keys[i];
          const childContext = context.childContextForFieldPath(path);
          const value = this.runPreConverter(values[i], childContext);
          Iif (value instanceof DeleteFieldValueImpl) {
            // Add it to the field mask, but don't add anything to updateData.
            fieldMaskPaths.push(path);
          } else {
            const parsedValue = this.parseData(value, childContext);
            if (parsedValue != null) {
              fieldMaskPaths.push(path);
              updateData = updateData.set(path, parsedValue);
            }
          }
        }

        const mask = new FieldMask(fieldMaskPaths);
        return new ParsedUpdateData(updateData, mask, context.fieldTransforms);
      }

      /**
       * Parse a "query value" (e.g. value in a where filter or a value in a cursor
       * bound).
       */
      parseQueryValue(methodName: string, input: AnyJs): FieldValue {
        const context = new ParseContext(
          UserDataSource.QueryValue,
          methodName,
          FieldPath.EMPTY_PATH
        );
        const parsed = this.parseData(input, context);
        assert(parsed != null, 'Parsed data should not be null.');
        assert(
          context.fieldTransforms.length === 0,
          'Field transforms should have been disallowed.'
        );
        return parsed!;
      }

      /** Sends data through this.preConverter, handling any thrown errors. */
      private runPreConverter(input: AnyJs, context: ParseContext): AnyJs {
        try {
          return this.preConverter(input);
        } catch (e) {
          const message = errorMessage(e);
          throw context.createError(message);
        }
      }

      /**
       * Internal helper for parsing user data.
       *
       * @param input Data to be parsed.
       * @param context A context object representing the current path being parsed,
       * the source of the data being parsed, etc.
       * @return The parsed value, or null if the value was a FieldValue sentinel
       * that should not be included in the resulting parsed data.
       */
      private parseData(input: AnyJs, context: ParseContext): FieldValue | null {
        input = this.runPreConverter(input, context);
        if (looksLikeJsonObject(input)) {
          validatePlainObject('Unsupported field value:', context, input);
          return this.parseObject(input as Dict<AnyJs>, context);
        } else {
          // If context.path is null we are inside an array and we don't support
          // field mask paths more granular than the top-level array.
          if (context.path) {
            context.fieldMask.push(context.path);
          }

          if (input instanceof Array) {
            // TODO(b/34871131): Include the path containing the array in the error
            // message.
            if (context.arrayElement) {
              throw context.createError('Nested arrays are not supported');
            }
            return this.parseArray(input as AnyJs[], context);
          } else if (input instanceof FieldValueImpl) {
            // parseSentinelFieldValue() may add a FieldTransform, but we return
            // null since nothing should be included in the actual parsed data.
            this.parseSentinelFieldValue(input, context);
            return null;
          } else {
            return this.parseScalarValue(input, context);
          }
        }
      }

      private parseArray(array: AnyJs[], context: ParseContext): FieldValue {
        const result = [] as FieldValue[];
        let entryIndex = 0;
        for (const entry of array) {
          let parsedEntry = this.parseData(
            entry,
            context.childContextForArray(entryIndex)
          );
          Iif (parsedEntry == null) {
            // Just include nulls in the array for fields being replaced with a
            // sentinel.
            parsedEntry = NullValue.INSTANCE;
          }
          result.push(parsedEntry);
          entryIndex++;
        }
        return new ArrayValue(result);
      }

      private parseObject(obj: Dict<AnyJs>, context: ParseContext): FieldValue {
        let result = new SortedMap<string, FieldValue>(primitiveComparator);
        objUtils.forEach(obj, (key: string, val: AnyJs) => {
          const parsedValue = this.parseData(
            val,
            context.childContextForField(key)
          );
          if (parsedValue != null) {
            result = result.insert(key, parsedValue);
          }
        });
        return new ObjectValue(result);
      }

      /**
       * Helper to parse a scalar value (i.e. not an Object or Array)
       *
       * @return The parsed value, or null if the value was a FieldValue sentinel
       * that should not be included in the resulting parsed data.
       */
      private parseScalarValue(
        value: AnyJs,
        context: ParseContext
      ): FieldValue | null {
        if (value === null) {
          return NullValue.INSTANCE;
        } else if (typeof value === 'number') {
          if (typeUtils.isSafeInteger(value)) {
            return new IntegerValue(value);
          } else {
            return new DoubleValue(value);
          }
        } else if (typeof value === 'boolean') {
          return BooleanValue.of(value);
        } else if (typeof value === 'string') {
          return new StringValue(value);
        } else if (value instanceof Date) {
          return new TimestampValue(Timestamp.fromDate(value));
        } else if (value instanceof Timestamp) {
          // Firestore backend truncates precision down to microseconds. To ensure
          // offline mode works the same with regards to truncation, perform the
          // truncation immediately without waiting for the backend to do that.
          return new TimestampValue(
            new Timestamp(
              value.seconds,
              Math.floor(value.nanoseconds / 1000) * 1000
            )
          );
        } else if (value instanceof GeoPoint) {
          return new GeoPointValue(value);
        } else if (value instanceof Blob) {
          return new BlobValue(value);
        } else if (value instanceof DocumentKeyReference) {
          return new RefValue(value.databaseId, value.key);
        } else {
          throw context.createError(
            `Unsupported field value: ${valueDescription(value)}`
          );
        }
      }

      /**
       * "Parses" the provided FieldValueImpl, adding any necessary transforms to
       * context.fieldTransforms.
       */
      private parseSentinelFieldValue(
        value: FieldValueImpl,
        context: ParseContext
      ): void {
        // Sentinels are only supported with writes, and not within arrays.
        Iif (!isWrite(context.dataSource)) {
          throw context.createError(
            `${value.methodName} can only be used with update() and set()`
          );
        }
        Iif (context.path === null) {
          throw context.createError(
            `${value.methodName} is not currently supported inside arrays`
          );
        }

        if (value instanceof DeleteFieldValueImpl) {
          if (context.dataSource === UserDataSource.MergeSet) {
            // No transform to add for a delete, so we do nothing.
          } else if (context.dataSource === UserDataSource.Update) {
            assert(
              context.path == null || context.path.length > 0,
              'FieldValue.delete() at the top level should have already' +
                ' been handled.'
            );
            throw context.createError(
              'FieldValue.delete() can only appear at the top level ' +
                'of your update data'
            );
          } else {
            // We shouldn't encounter delete sentinels for queries or non-merge set() calls.
            throw context.createError(
              'FieldValue.delete() cannot be used with set() unless you pass ' +
                '{merge:true}'
            );
          }
        } else Eif (value instanceof ServerTimestampFieldValueImpl) {
          context.fieldTransforms.push(
            new FieldTransform(context.path, ServerTimestampTransform.instance)
          );
        } else {
          fail('Unknown FieldValue type: ' + value);
        }
      }
    }

    /**
     * Checks whether an object looks like a JSON object that should be converted
     * into a struct. Normal class/prototype instances are considered to look like
     * JSON objects since they should be converted to a struct value. Arrays, Dates,
     * GeoPoints, etc. are not considered to look like JSON objects since they map
     * to specific FieldValue types other than ObjectValue.
     */
    function looksLikeJsonObject(input: AnyJs): boolean {
      return (
        typeof input === 'object' &&
        input !== null &&
        !(input instanceof Array) &&
        !(input instanceof Date) &&
        !(input instanceof Timestamp) &&
        !(input instanceof GeoPoint) &&
        !(input instanceof Blob) &&
        !(input instanceof DocumentKeyReference) &&
        !(input instanceof FieldValueImpl)
      );
    }

    function validatePlainObject(
      message: string,
      context: ParseContext,
      input: AnyJs
    ) {
      if (!looksLikeJsonObject(input) || !isPlainObject(input)) {
        const description = valueDescription(input);
        Iif (description === 'an object') {
          // Massage the error if it was an object.
          throw context.createError(message + ' a custom object');
        } else {
          throw context.createError(message + ' ' + description);
        }
      }
    }

    /**
     * Helper that calls fromDotSeparatedString() but wraps any error thrown.
     */
    export function fieldPathFromArgument(
      methodName: string,
      path: string | ExternalFieldPath
    ): FieldPath {
      if (path instanceof ExternalFieldPath) {
        return path._internalPath;
      } else Eif (typeof path === 'string') {
        return fieldPathFromDotSeparatedString(methodName, path);
      } else {
        const message = 'Field path arguments must be of type string or FieldPath.';
        throw new FirestoreError(
          Code.INVALID_ARGUMENT,
          `Function ${methodName}() called with invalid data. ${message}`
        );
      }
    }

    /**
     * Wraps fromDotSeparatedString with an error message about the method that
     * was thrown.
     * @param methodName The publicly visible method name
     * @param path The dot-separated string form of a field path which will be split
     * on dots.
     */
    function fieldPathFromDotSeparatedString(
      methodName: string,
      path: string
    ): FieldPath {
      try {
        return fromDotSeparatedString(path)._internalPath;
      } catch (e) {
        const message = errorMessage(e);
        throw new FirestoreError(
          Code.INVALID_ARGUMENT,
          `Function ${methodName}() called with invalid data. ${message}`
        );
      }
    }

    /**
     * Extracts the message from a caught exception, which should be an Error object
     * though JS doesn't guarantee that.
     */
    function errorMessage(error: Error | object): string {
      return error instanceof Error ? error.message : error.toString();
    }