helpers to build user scripts

helpers.js

/**
* Observe dom mutation and return a promise with the element when element is either present or appear on the page
*/
function waitForElm(selector) {
    return new Promise(resolve => {
        if (document.querySelector(selector)) {
            return resolve(document.querySelector(selector));
        }
        const observer = new MutationObserver(mutations => {
            if (document.querySelector(selector)) {
                observer.disconnect();
                resolve(document.querySelector(selector));
            }
        });
        observer.observe(document.body, {
            childList: true,
            subtree: true
        });
    });
}

/**
* Observe dom mutation and return a promise when the element is either not present or removed
*/
function waitForElmRemoved(selector) {
    return new Promise(resolve => {
        if (!document.querySelector(selector)) {
            return resolve(document.querySelector(selector));
        }
        const observer = new MutationObserver(mutations => {
            if (!document.querySelector(selector)) {
                observer.disconnect();
                resolve();
            }
        });
        observer.observe(document.body, {
            childList: true,
            subtree: true
        });
    });
}

/**
* Copy to clipboard
*/
const copyToClipboard = (value) => {
    const dummy = document.createElement(‘textarea’)
    document.body.appendChild(dummy)
    dummy.value = value
    dummy.select()
    document.execCommand(‘copy’)
    document.body.removeChild(dummy)
}