There are four main data structures in JavaScript - objects, arrays, maps, and sets. Each has its own strengths and weaknesses, and knowing when to use each is important for writing efficient code.
Objects are the most general data structure in JavaScript. They are key-value pairs, where the keys can be any data type, including numbers, strings, and even other objects. The values can be any data type as well, including functions. Objects are good for storing data that doesn't fit into a predefined structure, such as a user's profile on a social networking site.
Arrays are ordered lists of data. The items in an array can be of any data type, including objects. Arrays are good for storing data that needs to be accessed in a specific order, such as a list of products in a shopping cart.
Maps are key-value pairs, like objects, but the keys can only be strings or numbers. The values can be any data type. Maps are good for storing data that needs to be mapped to specific keys, such as a list of countries and their corresponding codes.
Sets are collections of data, like arrays, but the items in a set can't be duplicated. Sets are good for storing data that needs to be unique, such as a list of user IDs.
Performance
ㅤ | Array | Object | Map | Set |
Lookup | O(1) | O(1) | O(1) | O(1) |
Insertion | O(n) | O(1) | O(1) | O(1) |
ㅤ | ㅤ | ㅤ | ㅤ | ㅤ |