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20220330_Vote/Ewide.Web.Entry/wwwroot/lib/xe-utils/throttle.js

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+/**
+  * 节流函数；当被调用 n 毫秒后才会执行，如果在这时间内又被调用则至少每隔 n 秒毫秒调用一次该函数
+  *
+  * @param {Function} callback 回调
+  * @param {Number} wait 多少秒毫
+  * @param {Object} options 参数{leading: 是否在之前执行, trailing: 是否在之后执行}
+  * @return {Function}
+  */
+function throttle (callback, wait, options) {
+  var args, context
+  var opts = options || {}
+  var runFlag = false
+  var isDestroy = false
+  var timeout = 0
+  var optLeading = 'leading' in opts ? opts.leading : true
+  var optTrailing = 'trailing' in opts ? opts.trailing : false
+  var runFn = function () {
+    if (!isDestroy) {
+      runFlag = true
+      callback.apply(context, args)
+      timeout = setTimeout(endFn, wait)
+    }
+  }
+  var endFn = function () {
+    timeout = 0
+    if (!isDestroy && !runFlag && optTrailing === true) {
+      runFn()
+    }
+  }
+  var cancelFn = function () {
+    var rest = timeout !== 0
+    clearTimeout(timeout)
+    args = null
+    context = null
+    runFlag = false
+    timeout = 0
+    return rest
+  }
+  var throttled = function () {
+    args = arguments
+    context = this
+    runFlag = false
+    if (timeout === 0) {
+      if (optLeading === true) {
+        runFn()
+      } else if (optTrailing === true) {
+        timeout = setTimeout(endFn, wait)
+      }
+    }
+  }
+  throttled.cancel = cancelFn
+  return throttled
+}
+
+module.exports = throttle