uikit/src/js/util/fastdom.js

UIkit is a lightweight and modular front-end framework for developing fast and powerful web interfaces.

/*
    Based on:
    Copyright (c) 2016 Wilson Page wilsonpage@me.com
    https://github.com/wilsonpage/fastdom
*/

export const fastdom = { read, write, clear, flush };

const reads = [];
const writes = [];

function read(task) {
    reads.push(task);
    scheduleFlush();
    return task;
}

function write(task) {
    writes.push(task);
    scheduleFlush();
    return task;
}

function clear(task) {
    remove(reads, task);
    remove(writes, task);
}

let scheduled = false;
function flush() {
    runTasks(reads);
    runTasks(writes.splice(0));

    scheduled = false;

    if (reads.length || writes.length) {
        scheduleFlush();
    }
}

function scheduleFlush() {
    if (!scheduled) {
        scheduled = true;
        queueMicrotask(flush);
    }
}

function runTasks(tasks) {
    let task;
    while ((task = tasks.shift())) {
        try {
            task();
        } catch (e) {
            console.error(e);
        }
    }
}

function remove(array, item) {
    const index = array.indexOf(item);
    return ~index && array.splice(index, 1);
}