Learn to navigate Javascript objects efficiently using Object.keys(), Object.values(), and Object.entries() methods to access and manipulate data.
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...
// 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[...
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...
("\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....
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) { ...
(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', '...
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 ...
// Create an Object const person = { firstName: "John", lastName: "Doe", age: 50, eyeColor: "blue" }; // Get the Keys const keys = Object.keys(person); Try it Yourself » JavaScript for...in LoopThe JavaScript for...in statement loops through the properties of an object.Sy...