Getting the <script> scope into @html evaluation

[pauleveritt]

Imagine I have hello.webc:

<p>
    <span @html="this.firstName">Hello</span>
</p>
<script>
    export const firstName="Zach";
</script>

I couldn't find an explanation of that is the scope inside the JS evaluation for @html.
It looks like evaluateAttribute is where the scope is collected:

	// Used for @html and webc:if
	async evaluateAttribute(name, attrContent, options) {
		let data = Object.assign({}, this.helpers, options.componentProps, this.globalData);
		let content = await ModuleScript.evaluateScript(name, attrContent, data, {
			filePath: options.closestParentComponent || this.filePath
		});
		return content;
	}

[zachleat]

As also noted in #109:

<script webc:setup> will ship with WebC v0.9.0.

Has access to the standard stuff from the WebC data cascade: global data (Eleventy’s data cascade), helper functions, etc.

A few test cases here: https://github.com/11ty/webc/blob/efe23f6c12ac8505c52f9cfedc0bce6f4d0ad750/test/stubs/setup-script/test.js

• Any variable declarations or functions declared here will be available in the component (no need for export, just use a normal top-level variable declaration)
• Is async-friendly
• runs once per component (not once per instance, though the door is open for that later if we want it)