You can partially apply the function where you know the parameter; i.e. assign onDelete to:
this.handleDelete.bind(this, i)
If you did this.foo = this.foo.bind(this, props.bar) in the constructor then it would be the same function each time.
eg: it's going to be used as a event callback but you want the function signature to be foo(bar, event). Then you get the benefits of partial application without the problems of currying a new function each time its called.
source: have used this a lot for event handlers, especially when dealing with on 3rd party code.
I guess my point was that it doesn't scale to multiple children (which is effectively what the question was about). And whether you want to partially apply a bound function in the constructor or just bind and then have the function pick up the extra arg itself - it's the same thing. You end up with a single function that works with a single constant.
Though, in your case if props change, the partially applied function is now incorrect. Which is why I think I'm misunderstanding you.
> The interface is the same.
Huh? foo(event) is different from foo(bar, event) and if your function is only ever going to be called with the former (ie - any dom event handler) and you want the latter... it's absolutely useful.
Anyway, I see what you mean and it's a perfectly reasonable thing to do. Doesn't solve the original issue that was being discussed though :-)
In general binding like that in the constructor works only if you depend on props, but at that point, there isn't a need to bind at all since you can just reference the prop in the callback.