ZoneJs Error Using Angular 18 with MVC Project

Manoj Sridhar — Fri, 07 Feb 2025 15:03:09 +0000

I have a project that uses MVC .cshtml pages and use Angular components loaded in razor pages either with script tag or using iFrame.

We had been using Angular 5 before and loaded the scripts as below

<script type="text/javascript" src="@Url.Content("~/dist/polyfills.bundle.js")"></script>

<script type="text/javascript" src="@Url.Content("~/dist/main.bundle.js")"></script>

Now, we started converted it to Angular 18 and I tried to use the same pattern. Created new angular project using Angular cli.

ng new upgraded-angular

After doing ng build with default production configuration, I was using the following script to load the project.

<script type="text/javascript" src="@Url.Content("~/dist/upgraded-angular/browser/polyfills.js")"></script>

<script type="text/javascript" src="@Url.Content("~/dist/upgraded-angular/browser/main.js")"></script>

This gave me the below error and the component was not loaded

zone.js has detected that ZoneAwarePromise (window|global).Promise has been overwritten only when optimization is true.

Angular cli has correctly added zone.js to pollyfills as below in angular.json.

"polyfills": [
              "zone.js"
            ]

I tried all the steps in online but nothing worked. I figured out that the same worked fine when I do npm run watch which is running the build in development configuration. Also found in production configuration, if I used Optimization:false, the error was not happening.

Later I found the culprit to be the type that we use to load the script. Due to the adoption of ES modules by angular recent versions, we had to use type="module" for the script files. I changed my script to below and then I am now able to load angular 18 components in mvc.

<script type="module" src="@Url.Content("~/dist/upgraded-angular/browser/polyfills.js")"></script>

<script type="module" src="@Url.Content("~/dist/upgraded-angular/browser/main.js")"></script>

DEV Community: Manoj Sridhar

ZoneJs Error Using Angular 18 with MVC Project