add --exit-code, fixes #8

README.md

@@ -24,6 +24,7 @@ usage: updates [options]
     -g, --greatest [<pkg,...>]    Prefer greatest over latest version
     -i, --include <pkg,...>       Only include given packages
     -e, --exclude <pkg,...>       Exclude given packages
+    -E, --exit-code               Exit with code 2 on outdated packages
     -r, --registry <url>          Use a custom registry
     -f, --file <path>             Use specified package.json file
     -j, --json                    Output a JSON object

updates.js

@@ -13,6 +13,7 @@ const args = require("minimist")(process.argv.slice(2), {
     "v", "version",
   ],
   string: [
+    "E", "exit-code",
     "f", "file",
     "g", "greatest",
     "p", "prerelease",
@@ -24,6 +25,7 @@ const args = require("minimist")(process.argv.slice(2), {
   alias: {
     c: "color",
     e: "exclude",
+    E: "exit-code",
     f: "file",
     g: "greatest",
     h: "help",
@@ -46,6 +48,7 @@ if (args.help) {
     -g, --greatest [<pkg,...>]    Prefer greatest over latest version
     -i, --include <pkg,...>       Only include given packages
     -e, --exclude <pkg,...>       Exclude given packages
+    -E, --exit-code               Exit with code 2 on outdated packages
     -r, --registry <url>          Use a custom registry
     -f, --file <path>             Use specified package.json file
     -j, --json                    Output a JSON object
@@ -75,6 +78,11 @@ if (args["no-color"]) process.env.FORCE_COLOR = "0";
 const greatest = parseMixedArg(args.greatest);
 const prerelease = parseMixedArg(args.prerelease);
 
+let exitCode = parseMixedArg(args["exit-code"]);
+if (Array.isArray(exitCode) && exitCode.length) {
+  exitCode = true;
+}
+
 const registry = args.registry.endsWith("/") ? args.registry : args.registry + "/";
 const packageFile = args.file || require("find-up").sync("package.json");
 
@@ -206,7 +214,11 @@ function finish(obj, opts) {
     }
   }
 
-  process.exit(opts.exitCode || (output.error ? 1 : 0));
+  if (exitCode) {
+    process.exit(Object.keys(deps).length ? 2 : 0);
+  } else {
+    process.exit(opts.exitCode || (output.error ? 1 : 0));
+  }
 }
 
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