Alex Crichton 906cd7adcc Remove usage of wasm_import_module feature
This is now stabilized! Also tweak usage of it to the stable version.
2018-07-21 19:00:40 -07:00

98 lines
3.5 KiB
Rust

#![feature(use_extern_macros)]
extern crate wasm_bindgen;
extern crate js_sys;
use js_sys::Date;
use js_sys::JsString;
use wasm_bindgen::prelude::*;
#[wasm_bindgen]
extern "C" {
// Binding for the `setInverval` method in JS. This function takes a "long
// lived" closure as the first argument so we use `Closure` instead of
// a bare `&Fn()` which only surives for that one stack frame.
//
// The second argument is then the interval and the return value is how we
// clear this interval. We're not going to clear our interval in this
// example though so the return value is ignored.
#[wasm_bindgen(js_name = setInterval)]
fn set_interval(cb: &Closure<FnMut()>, delay: u32) -> f64;
// Bindings for `document` and various methods of updating HTML elements.
// Like with the `dom` example these'll ideally be upstream in a generated
// crate one day but for now we manually define them.
type HTMLDocument;
static document: HTMLDocument;
#[wasm_bindgen(method, js_name = getElementById)]
fn get_element_by_id(this: &HTMLDocument, id: &str) -> Element;
#[wasm_bindgen(method, js_name = getElementById)]
fn get_html_element_by_id(this: &HTMLDocument, id: &str) -> HTMLElement;
type Element;
#[wasm_bindgen(method, setter = innerHTML)]
fn set_inner_html(this: &Element, html: &str);
type HTMLElement;
#[wasm_bindgen(method, setter)]
fn set_onclick(this: &HTMLElement, cb: &Closure<FnMut()>);
#[wasm_bindgen(method, getter)]
fn style(this: &HTMLElement) -> CSS2Properties;
type CSS2Properties;
#[wasm_bindgen(method, setter)]
fn set_display(this: &CSS2Properties, display: &str);
}
#[wasm_bindgen]
pub fn run() {
// Set up a clock on our page and update it each second to ensure it's got
// an accurate date.
let a = Closure::new(update_time);
set_interval(&a, 1000);
update_time();
fn update_time() {
document
.get_element_by_id("current-time")
.set_inner_html(&String::from(
Date::new(JsValue::undefined())
.to_locale_string("en-GB".into(), JsValue::undefined()),
));
}
// We also want to count the number of times that our green square has been
// clicked. Our callback will update the `#num-clicks` div
let square = document.get_html_element_by_id("green-square");
let mut clicks = 0;
let b = Closure::new(move || {
clicks += 1;
document
.get_element_by_id("num-clicks")
.set_inner_html(&clicks.to_string());
});
square.set_onclick(&b);
// The instances of `Closure` that we created will invalidate their
// corresponding JS callback whenever they're dropped, so if we were to
// normally return from `run` then both of our registered closures will
// raise exceptions when invoked.
//
// Normally we'd store these handles to later get dropped at an appropriate
// time but for now we want these to be global handlers so we use the
// `forget` method to drop them without invalidating the closure. Note that
// this is leaking memory in Rust, so this should be done judiciously!
a.forget();
b.forget();
// And finally now that our demo is ready to go let's switch things up so
// everything is displayed and our loading prompt is hidden.
document
.get_html_element_by_id("loading")
.style()
.set_display("none");
document
.get_html_element_by_id("script")
.style()
.set_display("block");
}