add puppet helper class for store static puppet instance (#518)

src/puppet-accessory.spec.ts

+#!/usr/bin/env ts-node
+/**
+ *   Wechaty - https://github.com/chatie/wechaty
+ *
+ *   @copyright 2016-2018 Huan LI <zixia@zixia.net>
+ *
+ *   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.
+ *
+ */
+// tslint:disable:no-shadowed-variable
+import * as test  from 'blue-tape'
+// import * as sinon from 'sinon'
+
+import Puppet           from './puppet'
+import PuppetAccessory  from './puppet-accessory'
+
+const EXPECTED_PUPPET1 = {p: 1} as any as Puppet
+const EXPECTED_PUPPET2 = {p: 2} as any as Puppet
+
+test('PuppetAccessory smoke testing', async t => {
+  class FixtureClass extends PuppetAccessory {}
+  t.ok(FixtureClass.puppet === undefined, 'should be undefined initialy for static puppet')
+
+  const c = new FixtureClass()
+  t.throws(() => c.puppet, 'should throw if read instance puppet before initialization')
+
+  FixtureClass.puppet = EXPECTED_PUPPET1
+  t.equal(FixtureClass.puppet,  EXPECTED_PUPPET1, 'should get EXPECTED_PUPPET1 from static puppet after set static puppet')
+  t.equal(c.puppet,             EXPECTED_PUPPET1, 'should get EXPECTED_PUPPET1 from instance puppet after set static puppet')
+
+  c.puppet = EXPECTED_PUPPET2
+  t.equal(FixtureClass.puppet,  EXPECTED_PUPPET1, 'should get EXPECTED_PUPPET1 from static puppet after set instance puppet to EXPECTED_PUPPET2')
+  t.equal(c.puppet,             EXPECTED_PUPPET2, 'should get EXPECTED_PUPPET2 from instance puppet after set instance puppet to EXPECTED_PUPPET2')
+})

src/puppet-accessory.ts

+
+import { log }      from './config'
+import { Puppet }   from './puppet'
+
+export abstract class PuppetAccessory {
+  public static puppet?: Puppet
+
+  private _puppet?: Puppet
+
+  public set puppet(puppet: Puppet) {
+    log.verbose('PuppetAssessory', 'set puppet()')
+    this._puppet = puppet
+  }
+  public get puppet() {
+    log.silly('PuppetAssessory', 'get puppet()')
+
+    if (this._puppet) {
+      log.silly('PuppetAssessory', 'get puppet() from instance properties')
+      return this._puppet
+    }
+
+    const staticPuppet = (this.constructor as any).puppet
+    if (staticPuppet) {
+      log.silly('PuppetAssessory', 'get puppet() from static properties')
+      return staticPuppet
+    }
+
+    throw new Error('puppet not found')
+  }
+
+}
+
+export default PuppetAccessory