我们创建了带有 obj 对象的 loopNestedObj 函数。 在函数内部,我们有与前一个示例相同的循环。 但是,我们有一个 if 块来检查值的数据类型,看看它是否是一个对象。 如果是,那么我们调用 loopNestedObj 来循环遍历它的内容。 需要表达式 typeof value === ‘object’ && value !== null 来检查 value 是否是...
Example 1: Loop Through Object Using for...in // program to loop through an object using for...in loop const student = { name: 'John', age: 20, hobbies: ['reading', 'games', 'coding'], }; // using for...in for (let key in student) { let value; // get the value value...
方法1:使用Object.keys()和Array.map() 首先介绍一种基础但非常实用的方法,就是通过Object.keys()获取对象的键,然后用Array.map()把这些键对应的值提取出来。 代码语言:javascript 代码运行次数:0 AI代码解释 conststudent={name:'小明',age:18,city:'北京'};constarr=Object.keys(student).map(key=>student...
// logs ["sandwich", "chips", "drink"]letkeys=Object.keys(lunch);console.log(keys); You can combine it with afor...ofloop (or any of the other array techniques we looked at yesterday) to loop through the object. for(letkeyofObject.keys(lunch)){console.log(key);console.log(lunch[...
有一个变量第1行是一个整型，第10行变成了一个字符串，第20行又成了一个object，这样的代码让人...
Likewise, flow through object properties and global variables is not modeled. Type inference The library semmle.javascript.dataflow.TypeInference implements a simple type inference for JavaScript based on intraprocedural, heap-insensitive flow analysis. Basically, the inference algorithm approximates the ...
The JavaScriptfor/ofstatement loops through the values of an iterable objects. for/oflets you loop over data structures that are iterable such as Arrays, Strings, Maps, NodeLists, and more. Thefor/ofloop has the following syntax: for(variableofiterable) { ...
("\n\t\tCollections:\n");// loop through collectionsforawait(letcollectionofcollections) {// get collection clientconstcollectionClient = dbClient.collection(collection.name);// get doc count of collectionconstdocCount =awaitcollectionClient.countDocuments({});console.log(`\t\t\t${collection....
Object.getOwnPropertyDescriptor(): Object.defineProperties 设置属性特性的方法注意的规则: 详细见书中 重写extend工具函数: Object.defineProperty(Object.prototype,"extend", { writable:true, enumerable:false, configurable:true, value:function(o) {varnames = Object.getOwnPropertyNames(o);//Loop through them...
(iterator);// MapIterator { 'name', 'age', 'rank' }// `map.keys()` returns an iterator, not an array, so you can't// access the values using `[]`iterator[0];// undefined// The `for/of` loop can loop through iteratorsfor(constkeyofmap.keys()){key;// 'name', 'age', '...