docssetr.blogg.se - Reflection

#Reflection how to

Reflect.ownKeys() – return an array of the owned property keys (not inherited) of an object.

Reflect.isExtensible() – is the same as Object.isExtensible(). It returns a boolean indicating whether an property (either owned or inherited) exists.

Reflect.has() – work like the in operator, but as a function.

Reflect.getPrototypeOf() – is the same as Object.getPrototypeOf().

It returns a property descriptor of a property if the property exists on the object, or undefined otherwise.

Reflect.getOwnPropertyDescriptor() – is similar to Object.getOwnPropertyDescriptor().

Reflect.get() – return the value of a property.

It’s equivalent to calling the delete objectName. leteProperty() – behave like the delete operator, but as a function.fineProperty() – is similar to fineProperty(), but return a Boolean value indicating whether or not the property was successfully defined on the object.It is equivalent to calling new target(.args). nstruct() – act like the new operator, but as a function.Reflect.apply() – call a function with specified arguments.All the methods of the Reflect object are static. It is similar to the Math and JSON objects. It means that you cannot use Reflect with the new operator or invoke the Reflect as a function. Unlike the most global objects, the Reflect is not a constructor. The Reflect API is important because it allows you to develop programs and frameworks that are able to handle dynamic code. For example, methods like Object.keys(), Object.getOwnPropertyDescriptor(), and Array.isArray() are the classic reflection features.ĮS6 introduces a new global object called Reflect that allows you to call methods, construct objects, get and set properties, manipulate and extend properties. Prior to ES6, JavaScript already has reflection features even though they were not officially called that by the community or the specification.

In computer programming, reflection is the ability of a program to manipulate variables, properties, and methods of objects at runtime. Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century.Summary: in this tutorial, you will learn about the JavaScript reflection and Reflect API in ES6.Britannica Beyond We’ve created a new place where questions are at the center of learning.100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.

#Reflection how to

COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.This Time in History In these videos, find out what happened this month (or any month!) in history.#WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.Demystified Videos In Demystified, Britannica has all the answers to your burning questions.Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.