gulpuglify error how to convert code to es5 - gulp

Question

I am getting this error while trying to push my code to staging enviroment:
throw er; // Unhandled 'error' event
^
GulpUglifyError: unable to minify JavaScript
Is there any way to convert this code to ES5, I have no idea where to start or what the error is? Can you help me please?
//animated number counter
var stats = document.querySelectorAll(".counter");
stats.forEach(stat => {
var patt = /(\D+)?(\d+)(\D+)?(\d+)?(\D+)?/;
var time = 1000;
var result = [...patt.exec(stat.textContent)];
var fresh = true;
var ticks;
result.shift();
result = result.filter(res => res != null);
while (stat.firstChild) {
stat.removeChild(stat.firstChild);
}
for (var res of result) {
if (isNaN(res)) {
stat.insertAdjacentHTML("beforeend", `<span>${res}</span>`);
} else {
for (var i = 0; i < res.length; i++) {
stat.insertAdjacentHTML(
"beforeend",
`<span data-value="${res[i]}">
<span>–</span>
${Array(parseInt(res[i]) + 1)
.join(0)
.split(0)
.map(
(x, j) => `
<span>${j}</span>
`
)
.join("")}
</span>`
);
}
}
}
ticks = [...stat.querySelectorAll("span[data-value]")];
var activate = () => {
var top = stat.getBoundingClientRect().top;
var offset = window.innerHeight * 0.8;
setTimeout(() => {
fresh = false;
}, time);
if (top < offset) {
setTimeout(() => {
for (var tick of ticks) {
var dist = parseInt(tick.getAttribute("data-value")) + 1;
tick.style.transform = `translateY(-${dist * 100}%)`;
}
}, fresh ? time : 0);
window.removeEventListener("scroll", activate);
}
};
window.addEventListener("scroll", activate);
activate();
});