Should we have a basepath option/helper/plugin

[jakobrosenberg]

Currently basepaths can be set the following way

<script>
    ...
    const urlRewrite = {
        toExternal: url => '/subpath' + url,
        toInternal: url => url.replace(/^\/subpath/, ''),
    }
</script>

<Router ... {urlRewrite} />

Should we have a helper or plugin like

urlRewrite = basepath('/subpath')

Or should we do something even "simpler" and add a basepath option like this

<script>
    ...
    const basepath = '/subpath'
</script>

<Router ... {basepath} />

I'm hesitant about the last option as it requires bloating the core with code that duplicates functionality of urlRewrite.