NumericInput with value set does not behave as Controlled component

[ablakey]

Bug report

• Package version(s): 2.0.0-rc.2
• Browser and OS versions: Ubuntu 16.04, Chrome 64.0.3282.186

Steps to reproduce

1. Create a basic NumericInput component. It can be as simple as this:

<NumericInput
  value={1.0}
  onValueChange={v => console.log(v)}
/>

2. Type in a different value.
3. Notice that the value does change.

Actual behavior

The component freely changes value despite the value property being set to a constant.

Expected behavior

The component's value shall never change unless the value property is changed.

[ablakey]

Forgive me if I'm missing something. It looks like NumericInput is simply not implemented to be a controlled component, despite the documentation:

https://github.com/palantir/blueprint/blob/f4e9f758/packages/core/src/components/forms/numericInput.tsx#L180

I don't see anything that enforces that this.props.value takes precedence over this.state.value

The best I can guess is that it's "controlled" in the sense that this.props.value will just override this.state.value each re-render. But that does not help us if the component is not being re-rendered by its parent. What should happen is that changing the value invokes the onValueChange callback, but it does not cause an internal re-render (because state mutates) since this.props.value is not undefined.

[benjaminbours]

👍 I'm facing the same unexpected behaviour. Would be nice and probably not a lot of work to fix it, I Will do it soon if I got some time. This behaviour currently prevent me to implement a cleaner force value to integer, as described here. Because finally what you push into value, is only the first displayed value in the field, due to the internal re-render described by @ablakey

[benjaminbours]

Investigating, I realised this issue has already a duplicate here => #3553.

By the way, looking at my problem and the one mentioned in #3553, we comeback again to this use case about having kind of a mode integer for the component. It has been proposed #1956 but not accepted. I would like to encourage to reconsider it. Of course it's easy to do it yourself (when you have a real controlled component...) but the simplicity of just enable it is valuable from a user point of view. At least ensuring an alternative is working if it's not this precise solution.