Single selector kind

The Single selector kind is used to specify that the element is unique and its type will be known at compile time.

For example, the macro invocation below:

#![allow(unused)]
fn main() {
initialize_elements!(
    html: "../index.html",
    elements: {
        let header = Single("h1");
        let name_input = Single("#name-input");
    }
);
}

Will expand to the following code:

#![allow(unused)]
fn main() {
let window = web_sys::window().unwrap();
let document = window.document().unwrap();

let header: web_sys::HtmlElement = document
    .query_selector("h1")
    .unwrap()
    .unwrap()
    .dyn_into::<::web_sys::HtmlElement>()
    .unwrap();
let name_input: web_sys::HtmlInputElement = document
    .query_selector("#name-input")
    .unwrap()
    .unwrap()
    .dyn_into::<::web_sys::HtmlInputElement>()
    .unwrap();
}

assuming that the element with id name-input is an input element. The type of the header variable is web_sys::HtmlElement because there's no dedicated type for h1 elements in web_sys.

Arguments

The Single selector kind can also be seen a function where

• the first argument (mandatory) is the selector itself and
• the second argument (optional) is the "return type kind".

For example, the macro invocation below:

#![allow(unused)]
fn main() {
initialize_elements!(
    html: "index.html", elements: {
        let save_files_btn = Single("#save-files", RcT);
    }
);
}

will expand to the following code:

#![allow(unused)]
fn main() {
let window = web_sys::window().unwrap();
let document = window.document().unwrap();

let save_files_btn: std::rc::Rc<web_sys::HtmlButtonElement> = document
    .query_selector("#save-files")
    .unwrap()
    .unwrap()
    .dyn_into::<web_sys::HtmlButtonElement>()
    .unwrap()
    .into();
}

assuming that the element with id save-files is a button element.

You can learn more about return type kinds in the dedicated section.