On DOM Ready function

onDomReady.js

var domLoadedPromise = null

export default function onDomReady(documentReadyCallback) {
    if (!domLoadedPromise) {
        const readyReg = /complete|loaded|interactive/


        domLoadedPromise = new Promise(function (resolve) {
            if (readyReg.test(document.readyState) && document.body) {
                resolve()
            } else {
                document.addEventListener('DOMContentLoaded', function onDomLoaded() {
                    document.removeEventListener('DOMContentLoaded', onDomLoaded, false)
                    resolve()
                }, false)
            }
        })
    }

    if (documentReadyCallback) {
        domLoadedPromise.then(documentReadyCallback)
    }

    return domLoadedPromise
}