Show proper error if `start` and `now-start` scripts are missing

lib/read-metadata.js

@@ -1,8 +1,14 @@
+// Native
 const { basename, resolve: resolvePath } = require('path');
+
+// Packages
 const chalk = require('chalk');
 const { readFile, exists } = require('fs-promise');
 const { parse: parseDockerfile } = require('docker-file-parser');
 
+// Helpers
+const { error } = require('../lib/error');
+
 const listPackage = {
   scripts: {
     start: `NODE_ENV='production' serve ./content`
@@ -71,9 +77,10 @@ async function readMetaData(
       try {
         pkg = JSON.parse(await readFile(resolvePath(path, 'package.json')));
       } catch (err) {
-        const e = Error(`Failed to read JSON in "${path}/package.json"`);
-        e.userError = true;
-        throw e;
+        error(`Failed to read JSON in "${path}/package.json"`);
+
+        // eslint-disable-next-line unicorn/no-process-exit
+        process.exit(1);
       }
     }
 
@@ -81,12 +88,13 @@ async function readMetaData(
       strict &&
       (!pkg.scripts || (!pkg.scripts.start && !pkg.scripts['now-start']))
     ) {
-      const e = Error(
+      error(
         'Missing `start` (or `now-start`) script in `package.json`. ' +
           'See: https://docs.npmjs.com/cli/start.'
       );
-      e.userError = true;
-      throw e;
+
+      // eslint-disable-next-line unicorn/no-process-exit
+      process.exit(1);
     }
 
     if (!deploymentName) {