fix: Build exit non zero on failure (#153)

* CLI: exit 1 on error

Previously, a build failure would print the webpack errors, but exit 0
(with an unhandled promise rejection warning).

Note: this was true on node 10, not sure of the other platforms.

* Linter fixes: throw error instead of process.exit()

cli/index.js

@@ -6,6 +6,13 @@ const chalk = require('chalk');
 const version = require('../package').version;
 const {init} = require('./commands/init');
 
+// Make sure we die if we have an unhandled rejection (like a webpack build
+// failure)
+process.on('unhandledRejection', (err) => {
+ console.error(err);
+ throw new Error(`[packer-cli] ${err}`);
+});
+
 switch (process.argv[2]) {
  case 'init':
  init(args);