arr.forEach(function(ele) {console.log(ele); });// output: 1, 2// 上面代码等同于functionfunc(ele) {console.log(ele); }for(leti =0; i < arr.length; i++) {func(arr[i]) }// output: 1, 2 实际上forEach的polyfill实现也是这样的,在forEach函数中执行一个for循环,在for循环里调用回...
前言 本文925字,阅读大约需要7分钟。 总括: forEach循环中你不知道的3件事。 原文地址:3 things you didn’t know about the forEach loop in JS 公众号:「...
for (let i = "start" in window ? window.start : 0; i < 9; i++) { console.log(i); } // SyntaxError: 'for-in' loop variable declaration may not have an initializer. jsCopy to Clipboard // 将整个初始化器括起来 for (let i = ("start" in window ? window.start : 0); i <...
foreach就是用来一次遍历完数组左右元素的,如果有中断操作可以使用普通的for循环。 MDN上是这么解释的: There is no way to stop orbreaka forEach() loop other than by throwing an exception. If you need such behavior, the forEach() method is the wrong tool. Early termination may be accomplishedwi...
for...of 语句执行一个循环,该循环处理来自可迭代对象的值序列。可迭代对象包括内置对象的实例,例如 Array、String、TypedArray、Map、Set、NodeList(以及其他 DOM 集合),还包括 arguments 对象、由生成器函数生成的生成器,以及用户定义的可迭代对象。
平时工作中循环的使用场景可以说是非常之多了,昨天改别人代码时候有位同事非常喜欢用ES6等新特性,一个数组的遍历全部都是用for...of...,然后业务需求要用...
JS有几种循环语句: for for...in for...of(ES6 IE不支持) while do...while for each...in[2] (已废弃,不述) for await...in[3](异步,暂不述) ▉while[4] 语法: while (condition) statement 条件为真时执行语句,如此往复,直到条件为假。 多行语句可以用大括号包裹。 ▉do...while[5] 语法...
MDN文档上明确说明forEach循环是不可以退出的。 引自MDNThere is no way to stop or break a forEach() loop other than by throwing an exception. If you need such behavior, the forEach() method is the wrong tool.注意: 没有办法中止或者跳出 forEach() 循环,除了抛出一个异常。如果你需要这样,使...
I know that you landed on this page to know the direct way to break fromforEach(), but I’m sorry to tell you thatyou can’t. AsMDN: There is no way to stop or break aforEach()loop other than by throwing an exception. If you need such behavior, theforEach()method is the wro...
As theMDNdocumentation points out, if you need to break out of aforEachloop, then this method is the wrong tool. In this case, some better options would be: Built-inforloop (detailed below) Built-infor-ofloop (detailed below) Array.prototype.every() ...