refactor: drop dependency on is (#468)

package.json

@@ -49,13 +49,11 @@
     "arrify": "^2.0.0",
     "extend": "^3.0.2",
     "google-gax": "^1.11.1",
-    "is": "^3.2.1",
     "is-html": "^2.0.0",
     "protobufjs": "^6.8.8"
   },
   "devDependencies": {
     "@types/extend": "^3.0.0",
-    "@types/is": "0.0.21",
     "@types/mocha": "^7.0.0",
     "@types/node": "^10.5.7",
     "@types/proxyquire": "^1.3.28",

src/index.ts

@@ -1,18 +1,16 @@
-/*!
- * Copyright 2015 Google Inc. All Rights Reserved.
- *
- * 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.
- */
+// Copyright 2015 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
+//
+//     https://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 * as v2 from './v2';
 

src/v2/index.ts

@@ -1,10 +1,10 @@
-// Copyright 2017, Google LLC All rights reserved.
+// Copyright 2017 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
+//     https://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,
@@ -17,7 +17,6 @@ import {promisifyAll} from '@google-cloud/promisify';
 import arrify = require('arrify');
 import * as extend from 'extend';
 import {GoogleAuthOptions} from 'google-auth-library';
-import * as is from 'is';
 
 const isHtml = require('is-html');
 import {
@@ -331,7 +330,7 @@ export class Translate extends Service {
     callback?: GetLanguagesCallback
   ): void | Promise<[LanguageResult[], Metadata]> {
     let target: string;
-    if (is.fn(targetOrCallback)) {
+    if (typeof targetOrCallback === 'function') {
       callback = targetOrCallback as GetLanguagesCallback;
       target = 'en';
     } else {
@@ -344,7 +343,7 @@ export class Translate extends Service {
       qs: {},
     } as DecorateRequestOptions;
 
-    if (target && is.string(target)) {
+    if (target && typeof target === 'string') {
       reqOpts.qs.target = target;
     }
 
@@ -516,7 +515,7 @@ export class Translate extends Service {
       format: options.format || (isHtml(input[0]) ? 'html' : 'text'),
     };
 
-    if (is.string(options)) {
+    if (typeof options === 'string') {
       body.target = options;
     } else {
       if (options.from) {

system-test/translate.ts

@@ -1,18 +1,16 @@
-/*!
- * Copyright 2015 Google Inc. All Rights Reserved.
- *
- * 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.
- */
+// Copyright 2015 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
+//
+//     https://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 * as assert from 'assert';
 import {describe, it} from 'mocha';

test/index.ts

@@ -1,18 +1,16 @@
-/*!
- * Copyright 2015 Google Inc. All Rights Reserved.
- *
- * 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.
- */
+// Copyright 2015 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
+//
+//     https://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 {DecorateRequestOptions, util} from '@google-cloud/common';
 import {