perspective-view collapse / expand functions returning error

[ccarli]

Bug Report

I'm trying to use the perspective-view .collapse() method to displays the rows of my datagrid in a "grouped" state by default.
I'm not sure I'm using it correctly but when trying on one of the project's example I get the error message below

Steps to Reproduce:

1. open Superstore example
2. run in console

    viewer = document.querySelector("perspective-viewer[name='Sales Report']")  
    table = await viewer.getTable()
    view = await table.view()
    await view.collapse()

Expected Result:

update the datagrid display to group rows

Actual Result:

no action on datagrid and error message below

same behaviour / error message with methods .expand() and .set_depth()

[texodus]

Thanks for the report, @ccarli!

There are a few things conflated here. A View is kind of like a SQL query result set, but live - it holds the state and intermediate data for a set of query config values (e.g. what you put int he UI), including the expansions/collapse state of the tree (if it has one). The line view = await table.view() in your example creates a new View, e.g. not the one that your <perspective-viewer> UI created to render the data. That causes two issues:

• This new View has no config options, it was instantiated without an argument in your example, View(). Thus it is un-pivoted, and has no tree to collapse or expand, thus the error. The error is unfortunately obtuse - we'll get that fixed.
• Even if it had been pivoted, collapse()/expand() are being called on the wrong View, and won't affect the <perspective-viewer> UI as written.

In addition, you'll need to call .notifyResize(true) subsequently on the <perspective-viewer> to force it to redraw itself, because expand/collapse do not trigger data notifications (currently). So the correct code should look something like this:

viewer = document.querySelector("perspective-viewer[name='Sales Report']");
view = await viewer.getView();
await view.collapse();
await viewer.notifyResize(true);

... However, it appears the perspective-viewer re-write released in 1.0.0+ did not implement this method getView(), so this is not working in the most recent release yet (In versions <1.0.0, the .view property exists which allows this). I'll keep this report open to track this issue as well as the Error de-obfuscation issue above, these fixes should be in the 1.0.6 release.

[ccarli]

Very clear, thanks a lot!