Question

For instance, if I have:

<div data-bind="visible: viewModel.property1() || viewModel.property2()" />

… if viewModel.property1() is true, does knockout still evaluate viewModel.property2()?

Similarly, if we have:

<div data-bind="visible: viewModel.property1() && viewModel.property2()" />

… if viewModel.property1() is false, does knockout still evaluate viewModel.property2()?

If it does then I will bare this in mind when trying to optimise my bindings.

Thanks in advance.

Answer 1

Yes, it does short circuit.

The right hand side of the bindings is evaluated as a block of arbitrary javascript, and since && and || short cirtcuit in javascript…