/**
 * @license
 * Copyright 2020 Google LLC
 *
 * 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 { ParseContext } from '../api/parse_context';
import { FieldTransform } from '../model/mutation';
/**
 * Sentinel values that can be used when writing document fields with `set()`
 * or `update()`.
 */
export declare abstract class FieldValue {
    _methodName: string;
    /**
     * @param _methodName - The public API endpoint that returns this class.
     * @hideconstructor
     */
    constructor(_methodName: string);
    /** Compares `FieldValue`s for equality. */
    abstract isEqual(other: FieldValue): boolean;
    abstract _toFieldTransform(context: ParseContext): FieldTransform | null;
}