first commit

src/utils/index.js

@@ -0,0 +1,76 @@
+import dayjs from 'dayjs'
+
+/**
+ * @desc  格式化时间
+ * @param {(Object|string|number)} time
+ * @param {string} format
+ * @returns {string | null}
+ */
+export function formatDateTime(time = undefined, format = 'YYYY-MM-DD HH:mm:ss') {
+  return dayjs(time).format(format)
+}
+
+export function formatDate(date = undefined, format = 'YYYY-MM-DD') {
+  return formatDateTime(date, format)
+}
+
+/**
+ * @desc  函数节流
+ * @param {Function} fn
+ * @param {Number} wait
+ * @returns {Function}
+ */
+export function throttle(fn, wait) {
+  var context, args
+  var previous = 0
+
+  return function () {
+    var now = +new Date()
+    context = this
+    args = arguments
+    if (now - previous > wait) {
+      fn.apply(context, args)
+      previous = now
+    }
+  }
+}
+
+/**
+ * @desc  函数防抖
+ * @param {Function} func
+ * @param {number} wait
+ * @param {boolean} immediate
+ * @return {*}
+ */
+export function debounce(method, wait, immediate) {
+  let timeout
+  return function (...args) {
+    let context = this
+    if (timeout) {
+      clearTimeout(timeout)
+    }
+    // 立即执行需要两个条件，一是immediate为true，二是timeout未被赋值或被置为null
+    if (immediate) {
+      /**
+       * 如果定时器不存在，则立即执行，并设置一个定时器，wait毫秒后将定时器置为null
+       * 这样确保立即执行后wait毫秒内不会被再次触发
+       */
+      let callNow = !timeout
+      timeout = setTimeout(() => {
+        timeout = null
+      }, wait)
+      if (callNow) {
+        method.apply(context, args)
+      }
+    } else {
+      // 如果immediate为false，则函数wait毫秒后执行
+      timeout = setTimeout(() => {
+        /**
+         * args是一个类数组对象，所以使用fn.apply
+         * 也可写作method.call(context, ...args)
+         */
+        method.apply(context, args)
+      }, wait)
+    }
+  }
+}