/**

• 节流，多次触发，间隔时间段执行
• @param {Function} func
• @param {Int} wait
• @param {Object} options

*/

export function throttle(func, wait=500, options) {
    //container.onmousemove = throttle(getUserAction, 1000);
    var timeout, context, args
    var previous = 0
    if (!options) options = {leading:false,trailing:true}

    var later = function() {
        previous = options.leading === false ? 0 : new Date().getTime()
        timeout = null
        func.apply(context, args)
        if (!timeout) context = args = null
    }

    var throttled = function() {
        var now = new Date().getTime()
        if (!previous && options.leading === false) previous = now
        var remaining = wait - (now - previous)
        context = this
        args = arguments
        if (remaining <= 0 || remaining > wait) {
            if (timeout) {
                clearTimeout(timeout)
                timeout = null
            }
            previous = now
            func.apply(context, args)
            if (!timeout) context = args = null
        } else if (!timeout && options.trailing !== false) {
            timeout = setTimeout(later, remaining)
        }
    }
    return throttled
}

在开发中经常会有这样的需求，需要用到节流方法