fix: avoid adding unnecessary new line to .npmrc

Author: pvdlg

lib/set-npmrc-auth.js

@@ -25,10 +25,16 @@ module.exports = async (
   }
 
   if (NPM_USERNAME && NPM_PASSWORD && NPM_EMAIL) {
-    await outputFile(npmrc, `${currentConfig}\n_auth = \${LEGACY_TOKEN}\nemail = \${NPM_EMAIL}`);
+    await outputFile(
+      npmrc,
+      `${currentConfig ? `${currentConfig}\n` : ''}_auth = \${LEGACY_TOKEN}\nemail = \${NPM_EMAIL}`
+    );
     logger.log(`Wrote NPM_USERNAME, NPM_PASSWORD and NPM_EMAIL to ${npmrc}`);
   } else if (NPM_TOKEN) {
-    await outputFile(npmrc, `${currentConfig}\n${nerfDart(registry)}:_authToken = \${NPM_TOKEN}`);
+    await outputFile(
+      npmrc,
+      `${currentConfig ? `${currentConfig}\n` : ''}${nerfDart(registry)}:_authToken = \${NPM_TOKEN}`
+    );
     logger.log(`Wrote NPM_TOKEN to ${npmrc}`);
   } else {
     throw new AggregateError([getError('ENONPMTOKEN', {registry})]);

test/set-npmrc-auth.test.js

@@ -44,7 +44,7 @@ test.serial('Set auth with "NPM_USERNAME", "NPM_PASSWORD" and "NPM_EMAIL"', asyn
 
   await require('../lib/set-npmrc-auth')(npmrc, 'http://custom.registry.com', {cwd, env, logger: t.context.logger});
 
-  t.is((await readFile(npmrc)).toString(), `\n_auth = \${LEGACY_TOKEN}\nemail = \${NPM_EMAIL}`);
+  t.is((await readFile(npmrc)).toString(), `_auth = \${LEGACY_TOKEN}\nemail = \${NPM_EMAIL}`);
   t.deepEqual(t.context.log.args[1], [`Wrote NPM_USERNAME, NPM_PASSWORD and NPM_EMAIL to ${npmrc}`]);
 });