15条高效的JS技巧，你千万要收藏好了

1、延迟函数delay

const delay = ms => new Promise((resolve, reject) => setTimeout(resolve, ms)) const getData = status => new Promise((resolve, reject) => { status ? resolve('done') : reject('fail') }) const getRes = async (data) => { try { const res = await getData(data) const timestamp = new Date().getTime() await delay(1000) console.log(res, new Date().getTime() - timestamp) } catch (error) { console.log(error) } } getRes(true) // 隔了1秒

2、分割指定长度的元素数组

const listChunk = (list, size = 1, cacheList = []) => { const tmp = [...list] if (size <= 0) { return cacheList } while (tmp.length) { cacheList.push(tmp.splice(0, size)) } return cacheList } console.log(listChunk([1, 2, 3, 4, 5, 6, 7, 8, 9])) // [[1], [2], [3], [4], [5], [6], [7], [8], [9]] console.log(listChunk([1, 2, 3, 4, 5, 6, 7, 8, 9], 3)) // [[1, 2, 3], [4, 5, 6], [7, 8, 9]] console.log(listChunk([1, 2, 3, 4, 5, 6, 7, 8, 9], 0)) // [] console.log(listChunk([1, 2, 3, 4, 5, 6, 7, 8, 9], -1)) // []

3、获取数组交集

const intersection = (list, ...args) => list.filter(item => args.every(list => list.includes(item))) console.log(intersection([2, 1], [2, 3])) // [2] console.log(intersection([1, 2], [3, 4])) // []

4、函数柯里化

const curring = fn => { const { length } = fn const curried = (...args) => { return (args.length >= length ? fn(...args) : (...args2) => curried(...args.concat(args2))) } return curried } const listMerge = (a, b, c) => [a, b, c] const curried = curring(listMerge) console.log(curried(1)(2)(3)) // [1, 2, 3] console.log(curried(1, 2)(3)) // [1, 2, 3] console.log(curried(1, 2, 3)) // [1, 2, 3]

5、字符串前面空格去除与替换

const trimStart = str => str.replace(new RegExp('^([\\s]*)(.*)$'), '$2') console.log(trimStart(' abc ')) // abc console.log(trimStart('123 ')) // 123

6、字符串后面空格去除与替换

const trimEnd = str => str.replace(new RegExp('^(.*?)([\\s]*)$'), '$1') console.log(trimEnd(' abc ')) // abc console.log(trimEnd('123 ')) // 123

7、获取当前子元素是其父元素下子元素的排位

const getIndex = el => { if (!el) { return -1 } let index = 0 do { index++ } while (el = el.previousElementSibling); return index }

8、获取当前元素相对于document的偏移量

const getOffset = el => { const { top, left } = el.getBoundingClientRect() const { scrollTop, scrollLeft } = document.body return { top: top + scrollTop, left: left + scrollLeft } }

9、获取元素类型

const dataType = obj => Object.prototype.toString.call(obj).replace(/^\[object (.+)\]$/, '$1').toLowerCase();

10、判断是否是移动端

const isMobile = () => 'ontouchstart' in window

11、fade动画

const fade = (el, type = 'in') { el.style.opacity = (type === 'in' ? 0 : 1) let last = +new Date() const tick = () => { const opacityValue = (type === 'in' ? (new Date() - last) / 400 : -(new Date() - last) / 400) el.style.opacity = +el.style.opacity + opacityValue last = +new Date() if (type === 'in' ? (+el.style.opacity < 1) : (+el.style.opacity > 0)) { requestAnimationFrame(tick) } } tick() }

12、将指定格式的字符串解析为日期字符串

const dataPattern = (str, format = '-') => { if (!str) { return new Date() } const dateReg = new RegExp(`^(\\d{2})${format}(\\d{2})${format}(\\d{4})$`) const [, month, day, year] = dateReg.exec(str) return new Date(`${month}, ${day} ${year}`) } console.log(dataPattern('12-25-1995')) // Mon Dec 25 1995 00:00:00 GMT+0800 (中国标准时间)

13、禁止网页复制粘贴

const html = document.querySelector('html') html.oncopy = () => false html.onpaste = () => false

14、input框限制只能输入中文

const input = document.querySelector('input[type="text"]') const clearText = target => { const { value } = target target.value = value.replace(/[^\u4e00-\u9fa5]/g, '') } input.onfocus = ({target}) => { clearText(target) } input.onkeyup = ({target}) => { clearText(target) } input.onblur = ({target}) => { clearText(target) } input.oninput = ({target}) => { clearText(target) }

15、去除字符串的html代码

const removehtml = (str = '') => str.replace(/<[\/\!]*[^<>]*>/ig, '') console.log(removehtml('<h1>哈哈哈哈<呵呵呵</h1>')) // 哈哈哈哈<呵呵呵

本文完~