"lint" command for flipper-pkg tool

Summary:
Implemented json schema for flipper plugin package.json and used it for validation in "flipper-pkg lint" command.

Nice thing about json schema is that it not only allows to validate json, but also can be referenced using "$schema" property in json so IDEs like VSCode can find it and use for code completion, validation and to show properties documentation. I'm going to deploy the schema as a part of documentation website so it can be referenced as https://fbflipper.com/schemas/plugin-package/v2.json.

Also the "$schema" field can be used instead of "specVersion" to determine the specification according to which the plugin is defined. E.g., if specification version 3 would be created, it will be described in schema https://fbflipper.com/schemas/plugin-package/v3.json, etc.

Reviewed By: passy

Differential Revision: D21228294

fbshipit-source-id: f21351e584ef936a7d6b314436448489691f83a6

desktop/pkg/src/commands/bundle.ts

@@ -16,7 +16,7 @@ import {runBuild, getPluginDetails} from 'flipper-pkg-lib';
 export default class Bundle extends Command {
   public static description = 'transpiles and bundles plugin';
 
-  public static examples = [`$ flipper-pkg bundle optional/path/to/directory`];
+  public static examples = [`$ flipper-pkg bundle path/to/plugin`];
 
   public static args: args.IArg[] = [
     {

desktop/pkg/src/commands/lint.ts

@@ -0,0 +1,48 @@
+/**
+ * Copyright (c) Facebook, Inc. and its affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ * @format
+ */
+
+import {Command} from '@oclif/command';
+import {args} from '@oclif/parser';
+import path from 'path';
+import runLint from '../utils/runLint';
+
+export default class Lint extends Command {
+  public static description = 'validates a plugin package directory';
+
+  public static examples = [`$ flipper-pkg lint path/to/plugin`];
+
+  public static args: args.IArg[] = [
+    {
+      name: 'directory',
+      required: false,
+      default: '.',
+      description:
+        'Path to plugin package directory for linting. Defaults to the current working directory.',
+    },
+  ];
+
+  public async run() {
+    const {args} = this.parse(Lint);
+    const inputDirectory: string = path.resolve(process.cwd(), args.directory);
+    try {
+      console.log(`⚙️  Validating ${inputDirectory}`);
+      const errors = await runLint(inputDirectory);
+      if (errors) {
+        this.error(
+          `Plugin package definition is invalid. See https://fbflipper.com/docs/extending/js-setup.html#plugin-definition for details.\n${errors.join(
+            '\n',
+          )}`,
+        );
+      }
+    } catch (error) {
+      this.error(error);
+    }
+    console.log('✅  Plugin package definition is valid');
+  }
+}