fix: don't print when plugins that disabled by app is empty (#201)

Author: popomore

lib/loader/mixin/plugin.js

@@ -312,11 +312,13 @@ module.exports = {
       this.options.logger.info(`Following plugins will be enabled implicitly.\n${message}`);
 
       // should warn when the plugin is disabled by app
-      message = implicitEnabledPlugins
-        .filter(name => appPlugins[name] && appPlugins[name].enable === false)
-        .map(name => `  - ${name} required by [${requireMap[name]}]`)
-        .join('\n');
-      this.options.logger.warn(`Following plugins will be enabled implicitly that is disabled by application.\n${message}`);
+      const disabledPlugins = implicitEnabledPlugins.filter(name => appPlugins[name] && appPlugins[name].enable === false);
+      if (disabledPlugins.length) {
+        message = disabledPlugins
+          .map(name => `  - ${name} required by [${requireMap[name]}]`)
+          .join('\n');
+        this.options.logger.warn(`Following plugins will be enabled implicitly that is disabled by application.\n${message}`);
+      }
     }
 
     return result.sequence.map(name => allPlugins[name]);