hooks 3.0.0-alpha.15

Compile-time, async hooks
Documentation 
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
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158

use std::{marker::PhantomData, pin::Pin};

use hooks_core::{Hook, HookPollNextUpdate, HookUnmount, UpdateHook};

pin_project_lite::pin_project![
    #[derive(Debug)]
    pub struct LazyPinnedHook<H>
    where
        H: HookPollNextUpdate,
        H: HookUnmount,
    {
        #[pin]
        hook: Option<H>,
    }
];

impl<H: HookPollNextUpdate + HookUnmount> Default for LazyPinnedHook<H> {
    fn default() -> Self {
        Self { hook: None }
    }
}

impl<H: HookPollNextUpdate + HookUnmount> LazyPinnedHook<H> {
    #[inline]
    pub fn pin_project(self: Pin<&mut Self>) -> Pin<&mut Option<H>> {
        self.project().hook
    }

    #[inline]
    pub fn pin_project_hook(self: Pin<&mut Self>) -> Option<Pin<&mut H>> {
        self.pin_project().as_pin_mut()
    }
}
impl<H: Hook> LazyPinnedHook<H> {
    pub fn h(mut self: Pin<&mut Self>, into_hook: impl UpdateHook<Hook = H>) -> crate::Value<H> {
        if let Some(hook) = self.as_mut().pin_project_hook() {
            into_hook.update_hook(hook)
        } else {
            self.as_mut().pin_project().set(Some(into_hook.into_hook()))
        }

        H::use_hook(self.pin_project_hook().unwrap())
    }
}

hooks_core::impl_hook![
    impl<H: HookPollNextUpdate + HookUnmount> LazyPinnedHook<H> {
        fn unmount(self) {
            if let Some(hook) = self.pin_project_hook() {
                H::unmount(hook)
            }
        }

        fn poll_next_update(self, cx: _) {
            let hook = self.pin_project_hook();
            if let Some(hook) = hook {
                <H as HookPollNextUpdate>::poll_next_update(hook, cx)
            } else {
                std::task::Poll::Ready(false)
            }
        }

        #[inline(always)]
        fn use_hook(self) -> Pin<&'hook mut Self> {
            self
        }
    }
];

pub struct UseLazyPinnedHook<H: Hook>(PhantomData<H>);

/// Use another hook lazily so you can use hooks conditionally.
///
/// See also [`use_uninitialized_hook`](crate::use_uninitialized_hook).
///
/// The following code compiles but `use_effect()` actually does nothing
/// because `#[hook]` doesn't know the `use_effect` in `if` branch is a hook call.
///
#[cfg_attr(
    all(
        feature = "futures-core",
        feature = "proc-macro",
        feature = "use_shared_set",
        feature = "use_effect",
    ),
    doc = r###"
```
# use hooks::prelude::*;
#[hook]
fn use_demo() -> i32 {
    let (state, updater) = use_shared_set(0);
    if *state < 2 {
        use_effect(|v: &i32| updater.set(*v + 1), *state);
    }
    *state
}

# use futures_lite::StreamExt;
# futures_lite::future::block_on(async {
let values: Vec<_> = use_demo().into_hook_values().collect().await;
assert_eq!(values, [0])
# });
```
"###
)]
///
/// With [`use_lazy_pinned_hook`], we can call `use_effect` conditionally:
///
#[cfg_attr(
    all(
        feature = "futures-core",
        feature = "proc-macro",
        feature = "use_shared_set",
        feature = "use_effect",
    ),
    doc = r###"
```
# use hooks::prelude::*;
#[hook]
fn use_demo() -> i32 {
    let (state, updater) = use_shared_set(0);
    let hook_effect = use_lazy_pinned_hook();
    if *state < 2 {
        let updater = updater.clone();
        hook_effect.h(use_effect(move |v: &i32| updater.set(*v + 1), *state));
    }
    *state
}

# use futures_lite::StreamExt;
# futures_lite::future::block_on(async {
let values: Vec<_> = use_demo().into_hook_values().collect().await;
assert_eq!(values, [0, 1, 2])
# });
```
"###
)]
#[inline(always)]
pub fn use_lazy_pinned_hook<H: Hook>() -> UseLazyPinnedHook<H> {
    UseLazyPinnedHook(PhantomData)
}

hooks_core::impl_hook![
    impl<H: Hook> UseLazyPinnedHook<H> {
        #[inline]
        fn into_hook(self) -> LazyPinnedHook<H> {
            LazyPinnedHook::default()
        }

        #[inline]
        fn update_hook(self, _hook: _) {}

        #[inline]
        fn h(self, hook: LazyPinnedHook<H>) {
            hook
        }
    }
];