"init" command for flipper-pkg tool

Summary: Added command "init" to "flipper-pkg" which helps to quickly initialise Flipper desktop plugin.

Reviewed By: passy

Differential Revision: D21253819

fbshipit-source-id: 85a2fbde07ecb63737d180d2a7e5cc2846b4f533

desktop/pkg/templates/plugin/package.json.template

@@ -0,0 +1,25 @@
+{
+  "$schema": "https://fbflipper.com/schemas/plugin-package/v2.json",
+  "name": "flipper-plugin-{{package_name_suffix}}",
+  "id": "{{id}}",
+  "version": "1.0.0",
+  "main": "dist/bundle.js",
+  "flipperBundlerEntry": "src/index.tsx",
+  "license": "MIT",
+  "keywords": [
+    "flipper-plugin"
+  ],
+  "icon": "apps",
+  "title": "{{title}}",
+  "scripts": {
+    "lint": "flipper-pkg lint",
+    "prepack": "flipper-pkg lint && flipper-pkg bundle"
+  },
+  "peerDependencies": {
+    "flipper": "latest"
+  },
+  "devDependencies": {
+    "flipper": "latest",
+    "flipper-pkg": "latest"
+  }
+}

desktop/pkg/templates/plugin/src/index.tsx.template

@@ -0,0 +1,47 @@
+import React from 'react';
+import {FlipperPlugin, FlexColumn, KeyboardActions} from 'flipper';
+
+type State = {};
+
+type Data = {};
+
+type PersistedState = {
+  data: Array<Data>;
+};
+
+export default class extends FlipperPlugin<State, any, PersistedState> {
+  static keyboardActions: KeyboardActions = ['clear'];
+
+  static defaultPersistedState: PersistedState = {
+    data: [],
+  };
+
+  static persistedStateReducer = (
+    persistedState: PersistedState,
+    method: string,
+    data: Data,
+  ): PersistedState => {
+    return {
+      ...persistedState,
+      data: persistedState.data.concat([data]),
+    };
+  };
+
+  state = {};
+
+  onKeyboardAction = (action: string) => {
+    if (action === 'clear') {
+      this.props.setPersistedState({data: []});
+    }
+  };
+
+  render() {
+    return (
+      <FlexColumn>
+        {this.props.persistedState.data.map((d) => (
+          <div>{d}</div>
+        ))}
+      </FlexColumn>
+    );
+  }
+}