How can I access the browsers localStorage in Blazor?

I want to support JWTs, so I need to keep the token around; is there some facility to access this? Or should we just be registering our own javascript function to access this functionality for now?

Edit: per advice, I attempted to use JS interop as :

<script>
    localStorage.setItem("key1", "key1data");
    Blazor.registerFunction("readStorage", (key) => {
        return localStorage.getItem(key);
    });
</script>
@if (jwtKey == null)
{
<div class="login-panel">
    <p>JWT not loaded</p>
</div>
}
else
{
<div class="login-panel">
    <p>@jwtKey</p>
</div>
}

@functions {
    public RenderFragment Body { get; set; }
    string jwtKey;

    protected override async Task OnInitAsync()
    {
        jwtKey = RegisteredFunction.Invoke<string>("readStorage", "key1");
        if (jwtKey == null)
        {
            jwtKey = "Unknown";
        }
    }
}

But this results in a WASM error in diag:

WASM: [Microsoft.AspNetCore.Blazor.Browser.Interop.JavaScriptException] Could not find registered function with name 'readStorage'. WASM: Error: Could not find registered function with name 'readStorage'.

FYI, this is in the MainLayout.cshtml of the Blazor VS boilerplate project.

(can make a new Question if appropriate; somewhat related to this one though)