SOURCE

function debounce (fn, wait = 200) {
    var timerId = null;
    function helper () {
        if (timerId) {
            clearTimeout(timerId);
            timerId = null;
        }
        timerId = setTimeout (function () {
            fn();
        }, wait)
    }
    return helper;
}

// 高频计算
function calc () {
    console.log('calc trigger');
}
// calc();
// calc();
// calc();
// calc();
// calc();

const debouncedCalc = debounce(calc);
debouncedCalc();
debouncedCalc();
debouncedCalc();
debouncedCalc();
debouncedCalc();