Function that wait for an element to exist in DOM then return it.

get-dom-element-promise.js

export function getDomElement(selector = '', timeoutMs = 1000, pollIntervalMs = 10) {
    const timeStart = performance.now();
    return new Promise((resolve, reject) => {
        const intervalId = setInterval(() => {
            const timeNow = performance.now();
            const element = document.querySelector(selector);
            if (element) {
                clearInterval(intervalId);
                resolve(element);
            } else if ((timeNow - timeStart) > timeoutMs) {
                clearInterval(intervalId);
                reject(new Error('Timeout'));
            }
        }, pollIntervalMs);
    });
}

export function getDomElements(selector = '', timeoutMs = 1000, pollIntervalMs = 10) {
    const timeStart = performance.now();
    return new Promise((resolve, reject) => {
        const intervalId = setInterval(() => {
            const timeNow = performance.now();
            const elements = document.querySelectorAll(selector);
            if (elements) {
                clearInterval(intervalId);
                resolve(elements);
            } else if ((timeNow - timeStart) > timeoutMs) {
                clearInterval(intervalId);
                reject(new Error('Timeout'));
            }
        }, pollIntervalMs);
    });
}