separate compression algorithms to avoid circular dependency

packages/grpc-js/src/channel-options.ts

@@ -15,6 +15,8 @@
  *
  */
 
+import { CompressionAlgorithms } from './compression-algorithms';
+
 /**
  * An interface that contains options used when initializing a Channel instance.
  */
@@ -36,7 +38,7 @@ export interface ChannelOptions {
   'grpc.enable_http_proxy'?: number;
   'grpc.http_connect_target'?: string;
   'grpc.http_connect_creds'?: string;
-  'grpc.default_compression_algorithm'?: number;
+  'grpc.default_compression_algorithm'?: keyof typeof CompressionAlgorithms;
   'grpc-node.max_session_memory'?: number;
   // eslint-disable-next-line @typescript-eslint/no-explicit-any
   [key: string]: any;

packages/grpc-js/src/compression-algorithms.ts

@@ -0,0 +1,22 @@
+/*
+ * Copyright 2019 gRPC authors.
+ *
+ * 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.
+ *
+ */
+
+export const CompressionAlgorithms = {
+  0: 'identity',
+  1: 'deflate',
+  2: 'gzip'
+} as const;

packages/grpc-js/src/compression-filter.ts

@@ -19,16 +19,11 @@ import * as zlib from 'zlib';
 
 import { Call, WriteObject, WriteFlags } from './call-stream';
 import { Channel } from './channel';
+import { CompressionAlgorithms } from './compression-algorithms';
 import { BaseFilter, Filter, FilterFactory } from './filter';
 import { Metadata, MetadataValue } from './metadata';
 import { ChannelOptions } from './channel-options';
 
-export const CompressionAlgorithms = {
-  0: 'identity',
-  1: 'deflate',
-  2: 'gzip'
-} as const;
-
 const CompressionAlgorithKeys = new Set(Object.keys(CompressionAlgorithms));
 
 const isCompressionAlgorithmKey = (key: number | undefined): key is keyof typeof CompressionAlgorithms => {

packages/grpc-js/src/index.ts

@@ -25,7 +25,7 @@ import {
 import { CallCredentials, OAuth2Client } from './call-credentials';
 import { Deadline, StatusObject } from './call-stream';
 import { Channel, ChannelImplementation } from './channel';
-import { CompressionAlgorithms } from './compression-filter';
+import { CompressionAlgorithms } from './compression-algorithms';
 import { ConnectivityState } from './connectivity-state';
 import { ChannelCredentials } from './channel-credentials';
 import {