//映射对象集合到特定的属性名称的生成器。function*iteratePropertyValues(collection, property) {for(letobjectofcollection) {yieldobject[property]; } }//生成给定对象的每个值的生成器。function*iterateObjectValues(collection) {for(letkeyofObject.keys(collection)) {yieldcollection[key]; } }//生成给定数组...
We can easily loop over the key, values, and key/value pairs with for/of form. looping.js let stones = new Map(); stones.set(0, "citrine"); stones.set(1, "garnet"); stones.set(2, "topaz"); stones.set(3, "opal"); stones.set(4, "amethyst"); for (const entry of stones)...
tomatoes, onion}// iterate over values (amounts)for (let amount of recipeMap.values()) {alert(amount); // 500, 350, 50}// iterate over [key, value] entriesfor (let entry
};vardecaf =function(){this.name='decaf';this.basePrice=6; };// create object literals for the different sizesvarsmall = {getPrice:function(){returnthis.basePrice+2},getLabel:function(){returnthis.name+' small'} };varmedium = {getPrice:function(){returnthis.basePrice+4},getLabel:functi...
Create an Array Iterator, and then iterate over the key/value pairs: constfruits = ["Banana","Orange","Apple","Mango"]; constf = fruits.entries(); for(letx of f) { document.getElementById("demo").innerHTML+= x; } Try it Yourself » ...
function* iterateObjectValues(collection) { for (let key of Object.keys(collection)) { yield collection[key]; } } //生成给定数组中每个项的生成器。 function* iterateArrayElements(collection) { for (let element of collection) { yield element; } } 这些函数简洁小巧,易于使用。麻烦的是这些函数...
letuser={name:"John",age:30};// loop over keys-and-valuesfor(let[key,value]ofObject.entries(user)){alert(`${key}:${value}`);// name:John, then age:30} 对于Map 的遍历代码类似,它更简单一些,因为它是可迭代的: letuser=newMap();user.set("name","John");user.set("age","30")...
Use Object.keys() and Array.prototype.reduce() to iterate over each key with an appropriate initial value. Use Boolean to determine the truthiness of each key's value and add it to the accumulator if it's truthy. Use typeof to determine if a given value is an object and call the func...
to iterate over arrays, and Object.keys() / Object.values() / Object.entries() to produce arrays so you can iterate over objects. const numbers = [1, 2, 3, 4, 5]; // bad let sum = 0; for (let num of numbers) { sum += num; } sum === 15; // good let sum = 0; ...
JavaScript 语言是在 1994 年创建的,旨在使 Web 浏览器显示的文档具有动态行为。自那时以来,该语言已经发生了显著的演变,与此同时,Web 平台的范围和功能也迅速增长。今天,JavaScript 程序员可以将 Web 视为一个功能齐全的应用程序开发平台。Web 浏览器专门用于显示格式化文本和图像,但是,像本机操作系统一样,浏览器还...