Issue #30: Reworking TypeScript types in JSDoc. Making Svelte compone…

…nt a "newable" constructor type and also fixing the optional types by defining their defaults, so the generated .d.ts properly suffixes the "?" at the end of each optional field.

index.js

@@ -45,24 +45,29 @@ function renderElements(timestamp) {
 }
 
 
+/**
+ * @typedef {new(...args: any[]) => any} Newable         Type alias for a really generic class constructor
+ * @typedef {Newable}                    SvelteComponent Svelte component class constructor (basically a "newable" object)
+ */
+
 /**
  * Please see README.md for usage information.
  *
  * @param {object} opts Custom element options
  *
- * @param {any}       opts.component  Svelte component instance to incorporate into your custom element.
- * @param {string}    opts.tagname    Name of the custom element tag you'd like to define.
- * @param {string[]?} opts.attributes Optional array of attributes that should be reactively forwarded to the component when modified.
- * @param {boolean?}  opts.shadow     Indicates if we should build the component in the shadow root instead of in the regular ("light") DOM.
- * @param {string?}   opts.href       URL to the CSS stylesheet to incorporate into the shadow DOM (if enabled).
+ * @param {SvelteComponent} opts.component       The Svelte component *class* constructor to incorporate into your custom element (this is the imported component class, *not* an instance)
+ * @param {string}          opts.tagname         Name of the custom element tag you'd like to define.
+ * @param {string[]}        [opts.attributes=[]] Optional array of attributes that should be reactively forwarded to the component when modified.
+ * @param {boolean}         [opts.shadow=false]  Indicates if we should build the component in the shadow root instead of in the regular ("light") DOM.
+ * @param {string}          [opts.href=""]       URL to the CSS stylesheet to incorporate into the shadow DOM (if enabled).
  *
  * Experimental:
- * @param {boolean?}   opts.hydratable Light DOM slot hydration (specific to svelte-retag): Enables pre-rendering of the
+ * @param {boolean}  [opts.hydratable=false]   Light DOM slot hydration (specific to svelte-retag): Enables pre-rendering of the
  *                                     web component (e.g. SSR) by adding extra markers (attributes & wrappers) during
  *                                     rendering to enable svelte-retag to find and restore light DOM slots when
  *                                     restoring interactivity.
  *
- * @param {boolean|string?} opts.debugMode Hidden option to enable debugging for package development purposes.
+ * @param {boolean|string} [opts.debugMode=false] Hidden option to enable debugging for package development purposes.
  */
 export default function svelteRetag(opts) {
 	/**