deleting object properties doesn't trigger a render

Maybe this has been discussed at some point, maybe not, but I was surprised that

obj.b = 'foo';

…will trigger a re-render, but…

delete obj.b;

…won’t.

REPL: https://svelte.dev/repl/c5377d8c85e34735a792a29e1b2d1353?version=3.6.6

[pngwn]

I think the simplest approach is = sign will trigger an update.

[arggh]

After completing the tutorial a few weeks ago, the rules in the back of my head were:

1. Fiddling with arrays or objects using methods won’t cause re-renders
2. Fiddling with arrays or objects not using methods will cause re-renders

To me it’s more logical to group the different behaviors based on the fact that 1) are method calls, 2) are not.

// Won't re-render
arr.push(1);                              // as expected
arr.unshift(3);                           // as expected

// Will re-render
arr[3] = 4;                               // as expected

// Won't re-render
Object.assign(obj, { bar: 'foo' });       // as expected

// Will re-render
obj.foo = 'bar';                          // as expected
delete obj.foo;                           // Surprise!

I’m not going to die on this hill, but just wanted to point this out as being the more logical approach in my opinion.