[Javascript] Iterate Over Items with JavaScript's for-of Loop

最新推荐文章于 2023-05-19 10:50:56 发布

转载最新推荐文章于 2023-05-19 10:50:56 发布 · 60 阅读

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原文链接：http://www.cnblogs.com/Answer1215/p/7518550.html

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#javascript #ViewUI

本文介绍了ES6中引入的for...of循环的基本用法。for...of循环允许遍历可迭代对象（如数组、字符串、Set或Map），并直接获取每个元素的值，但不适用于普通对象。

In this lesson we will understand the For Of loop in Javascript which was introduced in ES6. The for-of loop lets you iterate of an itterable object (array, string, set, or map) and returns each objects value in a specified variable. This excludes plain objects as we will see in the lesson.

Object.prototype.objCustom = function() {}; 
Array.prototype.arrCustom = function() {};

let iterable = [3, 5, 7];
iterable.foo = 'hello';

for (let i in iterable) {
  console.log(i); // 0, 1, 2, "foo", "arrCustom", "objCustom"
}

for (let i in iterable) {
  if (iterable.hasOwnProperty(i)) {
    console.log(i); // 0, 1, 2, "foo"
  }
}

for (let i of iterable) {
  console.log(i); // 3, 5, 7
}