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
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

//! This module contains the implementation of a virtual text node `VText`.

use super::{Reform, VDiff, VNode};
use crate::utils::document;
use cfg_if::cfg_if;
use cfg_match::cfg_match;
use log::warn;
use std::cmp::PartialEq;
use std::fmt;
cfg_if! {
    if #[cfg(feature = "std_web")] {
        use stdweb::web::{Element, INode, Node, TextNode};
    } else if #[cfg(feature = "web_sys")] {
        use std::ops::Deref;
        use web_sys::{Element, Node, Text as TextNode};
    }
}

/// A type for a virtual
/// [`TextNode`](https://developer.mozilla.org/en-US/docs/Web/API/Document/createTextNode)
/// representation.
#[derive(Clone)]
pub struct VText {
    /// Contains a text of the node.
    pub text: String,
    /// A reference to the `TextNode`.
    pub reference: Option<TextNode>,
}

impl VText {
    /// Creates new virtual text node with a content.
    pub fn new(text: String) -> Self {
        VText {
            text,
            reference: None,
        }
    }
}

impl VDiff for VText {
    /// Remove VText from parent.
    fn detach(&mut self, parent: &Element) -> Option<Node> {
        let node = self
            .reference
            .take()
            .expect("tried to remove not rendered VText from DOM");
        let next_sibling = node.next_sibling();
        if parent.remove_child(&node).is_err() {
            warn!("Node not found to remove VText");
        }
        next_sibling
    }

    /// Renders virtual node over existing `TextNode`, but only if value of text had changed.
    fn apply(
        &mut self,
        parent: &Element,
        previous_sibling: Option<&Node>,
        ancestor: Option<VNode>,
    ) -> Option<Node> {
        assert!(
            self.reference.is_none(),
            "reference is ignored so must not be set"
        );
        let reform = {
            match ancestor {
                // If element matched this type
                Some(VNode::VText(mut vtext)) => {
                    self.reference = vtext.reference.take();
                    if self.text != vtext.text {
                        if let Some(ref element) = self.reference {
                            element.set_node_value(Some(&self.text));
                        }
                    }
                    Reform::Keep
                }
                Some(mut vnode) => Reform::Before(vnode.detach(parent)),
                None => Reform::Before(None),
            }
        };
        match reform {
            Reform::Keep => {}
            Reform::Before(next_sibling) => {
                let element = document().create_text_node(&self.text);
                if let Some(next_sibling) = next_sibling {
                    let next_sibling = &next_sibling;
                    #[cfg(feature = "web_sys")]
                    let next_sibling = Some(next_sibling);
                    parent
                        .insert_before(&element, next_sibling)
                        .expect("can't insert text before the next sibling");
                } else if let Some(next_sibling) = previous_sibling.and_then(|p| p.next_sibling()) {
                    let next_sibling = &next_sibling;
                    #[cfg(feature = "web_sys")]
                    let next_sibling = Some(next_sibling);
                    parent
                        .insert_before(&element, next_sibling)
                        .expect("can't insert text before next_sibling");
                } else {
                    #[cfg_attr(
                        feature = "std_web",
                        allow(clippy::let_unit_value, unused_variables)
                    )]
                    {
                        let result = parent.append_child(&element);
                        #[cfg(feature = "web_sys")]
                        result.expect("can't append node to parent");
                    }
                }
                self.reference = Some(element);
            }
        }
        self.reference.as_ref().map(|t| {
            let node = cfg_match! {
                feature = "std_web" => t.as_node(),
                feature = "web_sys" => t.deref().deref(),
            };
            node.to_owned()
        })
    }
}

impl fmt::Debug for VText {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "VText {{ text: {} }}", self.text)
    }
}

impl PartialEq for VText {
    fn eq(&self, other: &VText) -> bool {
        self.text == other.text
    }
}

#[cfg(test)]
mod test {
    use crate::{html, Component, ComponentLink, Html, ShouldRender};
    #[cfg(feature = "wasm_test")]
    use wasm_bindgen_test::{wasm_bindgen_test as test, wasm_bindgen_test_configure};

    #[cfg(feature = "wasm_test")]
    wasm_bindgen_test_configure!(run_in_browser);

    struct Comp;

    impl Component for Comp {
        type Message = ();
        type Properties = ();

        fn create(_: Self::Properties, _: ComponentLink<Self>) -> Self {
            Comp
        }

        fn update(&mut self, _: Self::Message) -> ShouldRender {
            unimplemented!();
        }

        fn view(&self) -> Html {
            unimplemented!();
        }
    }

    #[test]
    fn text_as_root() {
        html! {
            "Text Node As Root"
        };

        html! {
            { "Text Node As Root" }
        };
    }
}