1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
use yew::prelude::*;
use super::use_is_first_mount;
/// This hook ignores the first invocation (e.g. on mount).
/// The signature is exactly the same as the [`use_effect`] hook.
///
/// # Example
///
/// ```rust
/// # use yew::prelude::*;
/// # use log::debug;
/// #
/// use yew_hooks::prelude::*;
///
/// #[function_component(UseEffectUpdate)]
/// fn effect_update() -> Html {
/// use_effect_update(|| {
/// debug!("Running effect only on updates");
/// });
///
/// html! {
/// <>
/// </>
/// }
/// }
/// ```
#[hook]
pub fn use_effect_update<Callback, Destructor>(callback: Callback)
where
Callback: FnOnce() -> Destructor + 'static,
Destructor: TearDown,
{
let first = use_is_first_mount();
use_effect(move || {
if first {
Box::new(|| ()) as Box<dyn FnOnce()>
} else {
let d = callback();
Box::new(move || d.tear_down())
}
});
}
/// This hook is similar to [`use_effect_update`] but it accepts dependencies.
/// The signature is exactly the same as the [`use_effect_with`] hook.
#[hook]
pub fn use_effect_update_with_deps<Callback, Destructor, Dependents>(
callback: Callback,
deps: Dependents,
) where
Callback: FnOnce(&Dependents) -> Destructor + 'static,
Destructor: TearDown,
Dependents: PartialEq + 'static,
{
let first = use_is_first_mount();
use_effect_with(deps, move |deps| {
if first {
Box::new(|| ()) as Box<dyn FnOnce()>
} else {
let d = callback(deps);
Box::new(move || d.tear_down())
}
});
}