Fix runtime-usage detection logic

Refs #325

Author: NekR

lib/index.js

@@ -288,15 +288,15 @@ var OfflinePlugin = (function () {
 
       compiler.plugin('emit', function (compilation, callback) {
         var runtimeTemplatePath = _path3['default'].resolve(__dirname, '../tpls/runtime-template.js');
-        var runtimeFound = undefined;
+        var hasRuntime = true;
 
         if (compilation.fileDependencies.indexOf) {
-          runtimeFound = compilation.fileDependencies.indexOf(runtimeTemplatePath) === -1;
+          hasRuntime = compilation.fileDependencies.indexOf(runtimeTemplatePath) !== -1;
         } else if (compilation.fileDependencies.has) {
-          runtimeFound = compilation.fileDependencies.has(runtimeTemplatePath);
+          hasRuntime = compilation.fileDependencies.has(runtimeTemplatePath);
         }
 
-        if (runtimeFound && !_this2.__tests.ignoreRuntime) {
+        if (!hasRuntime && !_this2.__tests.ignoreRuntime) {
           compilation.errors.push(new Error('OfflinePlugin: Plugin\'s runtime wasn\'t added to one of your bundle entries. See this https://goo.gl/YwewYp for details.'));
           callback();
           return;

src/index.js

@@ -278,16 +278,16 @@ export default class OfflinePlugin {
     });
 
     compiler.plugin('emit', (compilation, callback) => {
-      const runtimeTemplatePath = path.resolve(__dirname, '../tpls/runtime-template.js')
-      let runtimeFound;
+      const runtimeTemplatePath = path.resolve(__dirname, '../tpls/runtime-template.js');
+      let hasRuntime = true;
 
       if (compilation.fileDependencies.indexOf) {
-        runtimeFound = compilation.fileDependencies.indexOf(runtimeTemplatePath) === -1;
+        hasRuntime = compilation.fileDependencies.indexOf(runtimeTemplatePath) !== -1;
       } else if (compilation.fileDependencies.has) {
-        runtimeFound = compilation.fileDependencies.has(runtimeTemplatePath);
+        hasRuntime = compilation.fileDependencies.has(runtimeTemplatePath);
       }
 
-      if (runtimeFound && !this.__tests.ignoreRuntime) {
+      if (!hasRuntime && !this.__tests.ignoreRuntime) {
         compilation.errors.push(
           new Error(`OfflinePlugin: Plugin's runtime wasn't added to one of your bundle entries. See this https://goo.gl/YwewYp for details.`)
         );