diff --git a/lib/workers/branch.js b/lib/workers/branch.js
index 15323f195b0afe31b6e149da4e7a109db2b615aa..0bd1968d18f670b3a8b2f1e38523ec5e85427172 100644
--- a/lib/workers/branch.js
+++ b/lib/workers/branch.js
@@ -54,7 +54,7 @@ async function getParentBranch(branchName, config) {
 async function getYarnLockFile(packageJson, config) {
   // Detect if a yarn.lock file is in use
   const yarnLockFileName = path.join(path.dirname(config.packageFile), 'yarn.lock');
-  if (await config.api.getFileContent(yarnLockFileName) === false) {
+  if (!await config.api.getFileContent(yarnLockFileName)) {
     return null;
   }
   // Copy over custom config files