wasm-bindgen/examples/char/index.js

import {chars} from './chars.js'
let imp = import('./char.js')
let mod;

let counters = [];
imp.then(wasm => {
    mod = wasm;
    addCounter();
    let b = document.getElementById('add-counter');
    if (!b) throw new Error('Unable to find #add-counter');
    b.addEventListener('click', ev => addCounter())
});

function addCounter() {
    let ctr = mod.Counter.new(randomChar(), 0);
    counters.push(ctr);
    update();
}

function update() {
    let container = document.getElementById('container');
    if (!container) throw new Error('Unable to find #container in dom');
    while (container.hasChildNodes()) {
        if (container.lastChild.id == "add-counter") break;
        container.removeChild(container.lastChild);
    }
    for (var i = 0; i < counters.length; i++) {
        let counter = counters[i];
        container.appendChild(newCounter(counter.key(), counter.count(), ev => {
            counter.increment();
            update();
        }))
    }
}

function randomChar() {
    console.log('randomChar');
    let idx = Math.floor(Math.random() * (chars.length - 1));
    console.log('index', idx);
    let ret = chars.splice(idx, 1)[0];
    console.log('char', ret);
    return ret;
}

function newCounter(key, value, cb) {
    let container = document.createElement('div');
    container.setAttribute('class', 'counter');
    let title = document.createElement('h1');
    title.appendChild(document.createTextNode('Counter ' + key));
    container.appendChild(title);
    container.appendChild(newField('Count', value));
    let plus = document.createElement('button');
    plus.setAttribute('type', 'button');
    plus.setAttribute('class', 'plus-button');
    plus.appendChild(document.createTextNode('+'));
    plus.addEventListener('click', cb);
    container.appendChild(plus);
    return container;
}

function newField(key, value) {
    let ret = document.createElement('div');
    ret.setAttribute('class', 'field');
    let name = document.createElement('span');
    name.setAttribute('class', 'name');
    name.appendChild(document.createTextNode(key));
    ret.appendChild(name);
    let val = document.createElement('span');
    val.setAttribute('class', 'value');
    val.appendChild(document.createTextNode(value));
    ret.appendChild(val);
    return ret;
}