diff --git a/lib/docker.js b/lib/docker.js
index 0f2e078..41a8bab 100644
--- a/lib/docker.js
+++ b/lib/docker.js
@@ -307,7 +307,7 @@ function dockerContainerInspect(containerID, payload) {
     process.nextTick(() => {
       containerID = containerID || '';
       if (typeof containerID !== 'string') {
-        resolve();
+        return resolve();
       }
       const containerIdSanitized = (util.isPrototypePolluted() ? '' : util.sanitizeShellString(containerID, true)).trim();
       if (containerIdSanitized) {
@@ -601,7 +601,7 @@ function dockerContainerProcesses(containerID, callback) {
     process.nextTick(() => {
       containerID = containerID || '';
       if (typeof containerID !== 'string') {
-        resolve(result);
+        return resolve(result);
       }
       const containerIdSanitized = (util.isPrototypePolluted() ? '' : util.sanitizeShellString(containerID, true)).trim();