JavaScript objects are fundamental to web development, encapsulating data with properties and methods for efficient management. They enable structured data storage and interaction with web pages through the DOM. Key features include object creation, property manipulation, the Map object for ordered key-value pairs, and the Date object for handling time. Converting between arrays and objects, and managing JSON data are also crucial skills.
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JavaScript objects are key-value pairs used to store and manage data in a structured manner
Constructor Function
Objects can be created using the 'new' keyword with a constructor function
Object Literal Notation
Objects can also be created using the object literal notation for a more concise definition
Objects can represent a wide range of entities and can perform actions on their data through methods
Object keys are strings used to identify properties within an object, while the Map object is a collection type that stores key-value pairs with keys of any type
The Object.keys() method returns an array of a given object's own enumerable property names, allowing for various operations such as counting properties or verifying key existence
The Map object has methods such as .set(), .get(), and .delete() for adding, retrieving, and removing key-value pairs, respectively
The Date object is a built-in object used for manipulating dates and times, crucial for tasks such as scheduling and time calculations
Instantiation
The Date object can be instantiated with 'new Date()' to yield the current date and time
Methods
Methods such as getFullYear(), getMonth(), and getTime() allow for extracting and manipulating specific parts of a date
The Date object is useful for tasks involving date computations, such as determining the time until a future event or formatting dates for display
Arrays are best for ordered collections, while objects are ideal for structured data and associated behaviors
Object.assign() Function
The Object.assign() function maps array indices to object keys for improved search efficiency
Object.fromEntries() Function
The Object.fromEntries() function transforms an array of key-value pair arrays into an object for more logical data organization
The Array.prototype.sort() method can be used with a custom comparison function to sort objects based on their properties
JSON (JavaScript Object Notation) is a data interchange format, and JSON.parse() converts JSON strings into JavaScript objects for manipulation within JavaScript code
Understanding how to convert between JSON and JavaScript objects is crucial for effectively managing structured data in web applications
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JavaScript Object Properties
Collection of key-value pairs; key is string, value can be any type.
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JavaScript Object Methods
Functions within an object; enable interaction with object's data.
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JavaScript and DOM
Objects represent page elements and browser environment in DOM.
