{"id":59666,"date":"2018-05-02T16:44:23","date_gmt":"2018-05-02T11:14:23","guid":{"rendered":"https:\/\/www.vskills.in\/certification\/tutorial\/?p=59666"},"modified":"2024-04-12T14:13:22","modified_gmt":"2024-04-12T08:43:22","slug":"typescript-decorators","status":"publish","type":"page","link":"https:\/\/www.vskills.in\/certification\/tutorial\/typescript-decorators\/","title":{"rendered":"TypeScript Decorators"},"content":{"rendered":"

TypeScript Decorators<\/h1>\n

With the introduction of Classes in TypeScript and ES6, there now exist certain scenarios that require additional features to support annotating or modifying classes and class members. Decorators provide a way to add both annotations and a meta-programming syntax for class declarations and members. Decorators are a stage 2 proposal for JavaScript and are available as an experimental feature of TypeScript.<\/p>\n

A Decorator is a special kind of declaration that can be attached to a class declaration, method, accessor, property, or parameter. Decorators use the form @expression, where expression must evaluate to a function that will be called at runtime with information about the decorated declaration.<\/p>\n

For example, given the decorator @sealed we might write the sealed function as follows:<\/p>\n

function sealed(target) {
\n\/\/ do something with ‘target’ …
\n}<\/p>\n

Decorator Factories<\/p>\n

If we want to customize how a decorator is applied to a declaration, we can write a decorator factory. A Decorator Factory is simply a function that returns the expression that will be called by the decorator at runtime.<\/p>\n

We can write a decorator factory in the following fashion:<\/p>\n

function color(value: string) { \/\/ this is the decorator factory
\nreturn function (target) { \/\/ this is the decorator
\n\/\/ do something with ‘target’ and ‘value’…
\n}
\n}<\/p>\n

IT Professionals, Web Developers, Web Programmers, IT students can Apply for the certification course to move ahead in their careers.<\/strong><\/p>\n

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