Merge pull request #1657 from finos/get-view

Implement `getView()`

Author: texodus

rust/perspective-viewer/src/rust/custom_elements/viewer.rs

@@ -234,6 +234,16 @@ impl PerspectiveViewerElement {
         Ok(result)
     }
 
+    /// Get the underlying `View` for thie viewer.
+    pub fn js_get_view(&self) -> js_sys::Promise {
+        let session = self.session.clone();
+        future_to_promise(async move {
+            session
+                .js_get_view()
+                .ok_or_else(|| JsValue::from("No table set"))
+        })
+    }
+
     /// Get the underlying `Table` for this viewer.
     ///
     /// # Arguments

rust/perspective-viewer/src/rust/session.rs

@@ -132,6 +132,10 @@ impl Session {
             .map(|x| x.unchecked_into::<JsValue>())
     }
 
+    pub fn js_get_view(&self) -> Option<JsValue> {
+        Some(self.borrow().view_sub.as_ref()?.get_view().as_jsvalue())
+    }
+
     pub fn is_column_expression_in_use(&self, name: &str) -> bool {
         self.borrow().config.is_column_expression_in_use(name)
     }

rust/perspective-viewer/src/ts/viewer.ts

@@ -190,6 +190,30 @@ export class HTMLPerspectiveViewerElement extends HTMLElement {
         return table;
     }
 
+    /**
+     * Returns the underlying `perspective.View` currently configured for this
+     * `<perspective-viewer>`.  Because ownership of the `perspective.View` is
+     * mainainted by the `<perspective-viewer>` it was created by, this `View`
+     * may become deleted (invalidated by calling `delete()`) at any time -
+     * specifically, it will be deleted whenever the `PerspectiveViewConfig`
+     * changes.  Because of this, when using this API, prefer calling
+     * `getView()` repeatedly over caching the returned `perspective.View`,
+     * especially in `async` contexts.
+     * @category Data
+     * @returns A `Promise` which ressolves to a `perspective.View`.
+     * @example <caption>Collapse grid to root</caption>
+     * ```javascript
+     * const viewer = document.querySelector("perspective-viewer");
+     * const view = await viewer.getView();
+     * await view.set_depth(0);
+     * ```
+     */
+    async getView(): Promise<perspective.View> {
+        await this.load_wasm();
+        const view = await this.instance.js_get_view();
+        return view;
+    }
+
     /**
      * Restore this element to a state as generated by a reciprocal call to
      * `save`.  In `json` (default) format, `PerspectiveViewerConfig`'s fields