Codegen: Add codegen.js wrapper around generate-specs.sh

Summary:
Adds a simple wrapper around the generate-specs.sh bash script.
Supports optional flags.

Usage:
`node ./codegen.js --srcs ./js --modules_library_name FBReactNativeSpec`

Remove unused `USE_FABRIC` envvar code from `generate-specs.sh`.

Changelog:
[Internal]

Reviewed By: fkgozali

Differential Revision: D30439132

fbshipit-source-id: 07099c1d899606ac2e679fac6d32ea2fa4af40fc

scripts/codegen.js

@@ -0,0 +1,54 @@
+#!/usr/bin/env node
+/**
+ * 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
+ */
+
+'use strict';
+
+require('shelljs/global');
+const yargs = require('yargs');
+const execSync = require('child_process').execSync;
+
+let argv = yargs.option('srcs', {
+    alias: 'srcs_dir',
+    type: 'string',
+    description: 'Path to JavaScript sources',
+}).option('modules_library_name', {
+    type: 'string',
+    description: 'Native modules interfaces library name',
+}).option('modules_output_dir', {
+    type: 'string',
+    description: 'Native modules interfaces output dir',
+}).option('components_library_name', {
+    type: 'string',
+    description: 'Native components interfaces library name',
+}).option('components_output_dir', {
+    type: 'string',
+    description: 'Native components interfaces output dir',
+}).argv;
+
+let env_vars = [];
+const { srcs_dir, modules_library_name, modules_output_dir, components_library_name, components_output_dir } = argv;
+
+if (srcs_dir) {
+    env_vars.push(`SRCS_DIR=${srcs_dir}`);
+}
+if (modules_library_name) {
+    env_vars.push(`MODULES_LIBRARY_NAME=${modules_library_name}`);
+}
+if (modules_output_dir) {
+    env_vars.push(`MODULES_OUTPUT_DIR=${modules_output_dir}`);
+}
+if (components_library_name) {
+    env_vars.push(`COMPONENTS_LIBRARY_NAME=${components_library_name}`);
+}
+if (components_output_dir) {
+    env_vars.push(`COMPONENTS_OUTPUT_DIR=${components_output_dir}`);
+}
+
+execSync(`${env_vars.join(' ')} ./generate-specs.sh`);