Aspnetcore: Potential Razor/Visual studio javascript bug

[ericgrantholland]

script defined above does gives script1006 due to the if condition clause. If you change the "distance<0" clause to true, everything works. I am guessing something in the razor engine may be causing this or I might be missing something simple.

[ericgrantholland]

Here is the script that does not return a script 1006

[rstropek]

I think you have found a bug. The < character in your original scripts leads to invalid JavaScript in the generated .g.cs file. Repro code:

<script>
    Blazor.registerFunction('JavaScriptAlert', (message) => {
        var distance = 5;
        if (distance < 0) {
            alert(message);
        }

        return true;
    });
</script>

Result in .g.cs:

    builder.OpenElement(8, "script");
            builder.AddContent(9, @"
    Blazor.registerFunction('JavaScriptAlert', (message) => {
        var distance = 5;
        if (distance ");
            builder.AddContent(10, "< 0) {\n            alert(message);\n        }\n\n        return true;\n    });\n");
            builder.CloseElement();

Workaround: Replace < in JavaScript with <. After that change, generated JavaScript is correct and works as expected.

@SteveSandersonMS can you confirm that this is a bug? Or is this intended behavior and special characters like < have to be escaped in Blazor templates?

[SteveSandersonMS]

Thanks for reporting this.

Firstly, you're correct that the misinterpretation of the < character does look like a Razor parser bug.

However, putting <script> elements inside Blazor components is almost always a mistake. Blazor components are added and removed dynamically, and that's not compatible with <script> tags in general, whose effects cannot be removed by removing them from the document.

I'll file a separate issue to track prevention of <script> elements inside Blazor components. That will address the underlying issue better.

[SteveSandersonMS]

Filed aspnet/AspNetCore#16218