JS utility to animate numeric values from one value to another

animateNumericValues.ts

/**
 * [animateNumericValues interpolates from one number to another with a max of 60 integers per second]
 * @param {Element} element   [The DOM element that will get interpolated]
 * @param {number}  fromValue [the first value]
 * @param {number}  toValue   [the final value]
 * @param {number}  speed     [how long the animation should take in milliseconds]
 * @param {delay}   delay     [any delay before it starts counting up]
 * @param {string}  appendString [optional string that gets appended to the value. E.g. "%"]
 */
function animateNumericValues({
    element = document.body,
    fromValue = 0,
    toValue = 0,
    speed = 1000,
    delay = 0,
    format = {},
    appendString = "",
} = {}) {
    // Ensure the numbers compute
    if (fromValue > toValue || toValue < 1) {
        console.warn("The from value is greater than than the too value or the toValue is less than 1");
        return;
    }

    // Create an array of all values between and including from and to
    var arrayOfValuesFromTo = [];
    for (let i = fromValue; i++ <= toValue; ) {
        arrayOfValuesFromTo.push(i);
    }

    // Timing adjuster
    let adjuster = speed / 1000;

    // Reduce the number of items to around 60
    let reduceToSixty = arrayOfValuesFromTo.reduce((arr, idx, elem, original) => {
        if (original.length <= 30) {
            arr.push(elem);
            return arr;
        }
        // We always want the first and last value
        // Get the difference of from and to and divide by 60 and then push every one of those values into the array
        if (idx === 1 || idx % Math.round((fromValue - toValue) / (10 * adjuster)) === 0) {
            arr.push(elem);
        }
        // We want the actual value of the final one
        if (idx === original.length) {
            arr.push(toValue);
        }
        return arr;
    }, []);

    // Handle any delay
    setTimeout(e => {
        writeToDom();
    }, delay);

    function writeToDom() {
        // Write the values into the DOM
        reduceToSixty.forEach((num, count) => {
            setTimeout(() => {
                element.textContent = `${num.toLocaleString("en-US", format)}${appendString}`;
            }, (speed / reduceToSixty.length) * count);
        });
    }
}

You might want to pass in another parameter for the toLocaleString to vary the lang format.