JavaScript Proxy
JavaScript Proxy is a built-in object that allows you to create a wrapper around another object (called the target) to intercept and redefine fundamental operations for that object, such as property access, assignment, and function invocation. It provides a powerful mechanism for implementing custom behavior, validation, logging, or virtualization of object interactions. Proxies are part of the ECMAScript 6 (ES6) specification and enable advanced metaprogramming capabilities in JavaScript.
Developers should learn and use JavaScript Proxy when they need to implement cross-cutting concerns like data validation, access control, or logging without modifying the original object's code, making it ideal for frameworks, libraries, and applications requiring dynamic behavior. It is particularly useful in scenarios such as creating reactive systems (e.g., in Vue.js 3), implementing object observers, or building APIs with custom getter/setter logic, as it offers fine-grained control over object operations in a non-invasive way.